High-temperature Magnetization Research Articles

High-temperature magnetism and crystallography of aYCrO3single crystal

Magnetization measurements and time-of-flight neutron powder-diffraction studies on the high-temperature (300--980 K) magnetism and crystal structure (321--1200 K) of a pulverized YCrO$_3$ single crystal have been performed. Temperature-dependent inverse magnetic susceptibility coincides with a piecewise linear function with five regimes, with which we fit a Curie-Weiss law and calculate the frustration factor $f$. The fit results indicate a formation of magnetic polarons between 300 and 540 K and a very strong magnetic frustration. By including one factor $\eta$ that represents the degree of spin interactions into the Brillouin function, we can fit well the applied-magnetic-field dependence of magnetization. No structural phase transition was observed from 321 to 1200 K. The average thermal expansions of lattice configurations (\emph{a}, \emph{b}, \emph{c}, and \emph{V}) obey well the Gr$\ddot{\textrm{u}}$neisen approximations with an anomaly appearing around 900 K, implying an isosymmetric structural phase transition, and display an anisotropic character along the crystallographic \emph{a}, \emph{b}, and \emph{c} axes with the incompressibility $K^a_0 > K^c_0 > K^b_0$. It is interesting to find that at 321 K, the local distortion size $\Delta$(O2) $\approx$ 1.96$\Delta$(O1) $\approx$ 4.32$\Delta$(Y) $\approx$ 293.89$\Delta$(Cr). Based on the refined Y-O and Cr-O bond lengths, we deduce the local distortion environments and modes of Y, Cr, O1, and O2 ions. Especially, the Y and O2 ions display obvious atomic displacement and charge subduction, which may shed light on the dielectric property of the YCrO$_3$ compound. Additionally, by comparing Kramers Mn$^{3+}$ with non-Kramers Cr$^{3+}$ ions, it is noted that being a Kramers or non-Kramers ion can strongly affect the local distortion size, whereas, it may not be able to change the detailed distortion mode.

Intrinsic ferromagnetism with high temperature, strong anisotropy and controllable magnetization in the CrX (X = P, As) monolayer

2D ferromagnetic (FM) materials with high temperature, large magnetocrystalline anisotropic energy (MAE), and controllable magnetization are highly desirable for novel nanoscale spintronic applications. Herein by using DFT and Monte Carlo simulations, we demonstrate the possibility of realizing intrinsic ferromagnetism in 2D monolayer CrX (X = P, As), which are stable and can be exfoliated from their bulk phase with a van der Waals layered structure. Following the Goodenough-Kanamori-Anderson (GKA) rule, the long-range ferromagnetism of CrX is caused via a 90° superexchange interaction along Cr-P(As)-Cr bonds. The Curie temperature of CrP is predicted to be 232 K based on a Heisenberg Hamiltonian model, while the Berezinskii-Kosterlitz-Thouless transition temperature of CrAs is as high as 855 K. In contrast to other 2D magnetic materials, the CrP monolayer exhibits a significant uniaxial MAE of 217 μeV per Cr atom originating from spin-orbit coupling. Analysis of MAE reveals that CrP favors easy out-of-plane magnetization, while CrAs prefers easy in-plane magnetization. Remarkably, hole and electron doping can switch the magnetization axis in between the in-plane and out-of-plane direction, allowing for the effective control of spin injection/detection in 2D structures. Our results offer an ideal platform for realizing 2D magnetoelectric devices such as spin-FETs in spintronics.

Blocking like it's hot: a synthetic chemists' path to high-temperature lanthanide single molecule magnets.

Progress in the synthesis, design, and characterisation of single-molecule magnets (SMMs) has expanded dramatically from curiosity driven beginnings to molecules that retain magnetization above the boiling point of liquid nitrogen. This is in no small part due to the increasingly collaborative nature of this research where synthetic targets are guided by theoretical design criteria. This article aims to summarize these efforts and progress from the perspective of a synthetic chemist with a focus on how chemistry can modulate physical properties. A simple overview is presented of lanthanide electronic structure in order to contextualize the synthetic advances that have led to drastic improvements in the performance of lanthanide-based SMMs from the early 2000s to the late 2010s.

Paleomagnetism and provenance of the lower Cambrian sedimentary rocks of the Udzha Uplift (north of the Siberian platform)

Lately, data have been increasingly indicating an unusual, abnormal state of the magnetic field at the boundary of the Precambrian and Phanerozoic. This fact significantly limits the possibility of employing the paleomagnetic approach for creating various paleoreconstructions in this time interval, and it allows a better understanding of the evolution of the Earth’s magnetic field. Until recently, there was no exact binding of Lower Cambrian sections bearing an anomalous paleomagnetic record to the chronostratigraphical chart, which made it impossible to obtain adequate estimates of the duration of the anomalous state of the magnetic field. In this study we present the results of a paleomagnetic study of the Lower Cambrian terrigenous-carbonate rocks of the Udzha and Anabar Uplifts (Emyaksa and Medvezh Formations). New evidence has been obtained of the anomalous paleomagnetic record in these rocks, which manifests itself in the objective existence of two significantly different directions of the high-temperature magnetization components, the formation of which cannot be explained by a later remagnetization. U-Pb dating of detrital zircons constrains the maximum depositional age of the Manykay and Emyaksa Formations to ~520 Ma, which, in combination with the faunistic characteristic of the upper part of the Emyaksa Formation, points to the Atdaban age of studied successions. The age constraints obtained indicate a specific paleomagnetic record, and due to the peculiarities of the generation of the geomagnetic field of the terminal Precambrian–Early Cambrian Period, trace the paleomagnetic record back to the Atdaban age, inclusive.

A new HTS dual stator linear permanent magnet Vernier machine with Halbach array for wave energy conversion

In this paper, a high-temperature superconductor-dual stator linear permanent magnet Vernier machine (HTS-DSLPMVM) with Halbach array has been proposed for wave energy conversion. In order to better investigate, this machine has been compared to the prototype double stator linear permanent magnet Vernier machine (DSLPMVM). Both of the machines operate based on magnetic gear effect. At lower speeds they have the ability to produce a high thrust force. DSLPMVM and HTS-DSLPMVM have the same structure. So that, DSLPMVM and HTS-DSLPMVM consist of two stators and one translator with a three-phase concentrated winding. Each phase has been located independently on the translator. Also, permanent magnet (PM) Halbach array with appropriate magnetic direction mounted among the slot of the translator. The innovation of the proposed machine is that HTS-Bulk is located between the slot of the stators to shield the leakage flux. The operation of the two machines has been compared and analysed using the finite element method (FEM). Results show that, HTS-Bulk makes back-EMF, air gap flux density, power factor and thrust force to increase significantly and inductance to decrease, which effectively improves the machine operation.

Magnetic and Dielectric Properties of Nano- and Micron-BiFeO3/LDPE Composites with Magnetization Treatments.

By means of magnetization treatments at ambient temperature and elevated temperatures, the nano- and micron-bismuth ferrate/low density polyethylene (BiFeO3/LDPE) dielectric composites are developed to explore the material processing method to modify the crystalline morphology, magnetic and dielectric properties. The magnetic field treatment can induce the dipole in the LDPE macromolecular chain which leads to preferred orientation of polyethylene crystal grains to the direction of the magnetization field. The surface morphology of the materials measured by atomic force microscope (AFM) implies that the LDPE macromolecular chains in BiFeO3/LDPE composites have been orderly arranged and form thicker lamellae accumulated with a larger spacing after high temperature magnetization, resulting in the increased dimension and orientation of spherulites. The residual magnetization intensities of BiFeO3/LDPE composites have been significantly improved by magnetization treatments at ambient temperature. After this magnetization at ambient temperature, the MR of nano- and micron-BiFeO3/LDPE composites approach to 4.415 × 10−3 and 0.690 × 10−3 emu/g, respectively. The magnetic moments of BiFeO3 fillers are arranged parallel to the magnetic field direction, leading to appreciable enhancement of the magnetic interactions between BiFeO3 fillers, which will inhibit the polarization of the electric dipole moments at the interface between BiFeO3 fillers and the LDPE matrix. Therefore, magnetization treatment results in the lower dielectric constant and higher dielectric loss of BiFeO3/LDPE composites. It is proven that the magnetic and dielectric properties of polymer dielectric composites can be effectively modified by the magnetization treatment in the melt blending process of preparing composites, which is expected to provide a technical strategy for developing magnetic polymer dielectrics.

Levitation and Lateral Stabilization Device Based on a Second-Generation High-Temperature Superconductor

The superconducting levitation device comprises a stationary magnetic rail of permanent magnets and a cryostat on a vehicle with a second-generation high-temperature tape superconductor placed in the cryostat, folded in a stack or wound by a coil on a non-magnetic frame without electrical connection of the ends and the transport current. Cool tape high-temperature superconductor of the second generation, folded in a stack or wound on a non magnetic frame in the form of axisymmetric or track coil, without electric connections of the ends and a transport current, behaves as a massive sample of a superconductor and the Meissner Oxenfeld effect, the magnetic field created by the magnetic rail is displaced from the volume of the superconductor, causing the power of levitation and the vehicle hangs over the track structure.
 The high critical parameters of the second-generation high-temperature superconductor belt ensure efficient operation of the superconducting levitation device.
 Aim: To demonstration the technical feasibility and efficiency of creating a levitation unit based on the use of a second-generation high-temperature superconductor and permanent magnets made of rare earth metals.
 Methods: Calculations of the magnetic field distribution in the combination of a magnetic rail and a massive superconductor, preliminary design of the levitation unit and experimental studies on the model.
 Results: Experiments on a model of a superconducting levitation device confirmed the efficiency of this technical solution and its effectiveness.
 Conclusion: an original technical solution is proposed that allows to significantly improve the energy characteristics of the levitation node by using a second-generation high-temperature superconductor operating in a passive mode without a transport current, using the partial Meissner-Oxenfeld effect and the engagement of quantized magnetic flux strands at the pinning centers.

MnBi Magnetic Material: A Critical Review

Manganese Bismuth (MnBi) - the ferromagnetic material attracting a great interest of the world magnetic society last years. The absence of rare-earth elements in compositions, the sizable magnetocrystalline anisotropy, the room-temperature moderate but high-temperature reasonable magnetization plus the positive temperature coefficient of coercivity and the moderate Curie temperature make MnBi bulk magnets very potential for high-temperature magnet application. This bright future is a little gray because the research results in the past were not as expected. The paper summarizes the results concerning the MnBi alloys, powders and bulk magnets investigated during past 67 years. The look on the difficulties inhibiting the development of this material is given and the proposals that might allow overcoming the difficulties and push again the efforts of research towards the goal of 12 MGOe for the energy product (BH)max of MnBi bulk magnets are discussed.

Effect of W/Co co-substitution on structural, microstructural, magnetic and electrical properties of Bi4NdFeTi3O15 aurivillius compound

Here, in this paper, we have reported the structural, microstructural, optical, ferroelectric and magnetic properties of Nd and W/Co co-substituted Bi4NdTi3−2x(W/Co2)xFeO15 (0.00 ≤ x ≤ 0.15) 4-layered Aurivillius multiferroic ceramics. These ceramics were prepared by conventional high-temperature solid-state reaction method. The room temperature (RT) X-ray diffraction (XRD) and Raman studies revealed that, these ceramics exhibits a pure orthorhombic structure with A21am space group. The surface morphology of these ceramic studies confirmed the formation of randomly oriented grains as non-uniform in size. Further, W/Co2 substitution in BNFT revealed the presence of asymmetrical shaped internal nano-size domains. The band gap of the ceramics was calculated and found to be decreased upon with increasing the concentration of W/Co2. All compounds exhibited improved P–E loops with unsaturated polarization upon substitution with enhance polarization and reduced coercive field. It was found that with higher substitution levels x ≥ 0.10 adversely affected the ferroelectric characteristics. The magnetic measurement revealed that Nd and W/Co co-substitution induced a strong ferromagnetic interaction via Fe3+–O–Co2+/3+ coupling. The high-temperature magnetization studies revealed the Curie temperature (TC) enhances as the W/Co2 concentration increase. Henceforth, the observed outcomes are emphasized for designing new single-phase room temperature multiferroics in future magnetoelectric applications.

Development of high-coercivity state in high-energy and high-temperature Sm-Co-Fe-Cu-Zr magnets upon step cooling

The work compares the peculiarities of the high-coercivity state formation in the Sm-Co-Fe-Cu-Zr high-temperature and high-energy permanent magnets (HTPM and HEPM) in the course of the heat treatment with the stepwise decreasing temperature from 830 to 400 °C. Two types of magnets with varying Fe concentration, i.e., Sm(Co0.88-xFexCu0.09Zr0.03)7 with x = 0–0.12 (the HTPMs) and Sm(Co0.91-xFexCu0.06 Zr0.03)7.5 with x = 0.24–0.33 (the HEPMs) were studied at different temperatures of heat treatment for phase formation by x-ray diffraction followed by magnetic property measurements. Microstructure characterization was performed using transmission electron microscopy, whereas the three-dimensional elemental distribution at near-atomic scale was obtained using atom probe tomography. In HEPMs, the main increase in coercivity and relaxation of stresses accompanied by intensive enrichment of the 1:5 phase in Cu are observed at high temperatures (Т ≈ 700 °C). In HTPMs, the coercivity monotonously increases in the entire temperature range of the slow cooling from 700 to 400 °C at a rate of 0.5 °C/s. At the temperature close to the Curie temperature (∼550 °C) of the Sm(Co,Cu)5-type phase, the anomaly of the coercivity increment has been observed. The interphase stresses grow and the elemental redistribution appears to be accelerated simultaneously. The non-uniform Cu distribution in the 1:5 phase can be described by the formation of Cu-rich interlayers at the interface of the Sm(Co,Cu)5 and Sm2(Co,Fe)17-type phases.

New paleomagnetic results from the ca. 1.68–1.63 Ga mafic dyke swarms in Western Shandong Province, Eastern China: Implications for the reconstruction of the Columbia supercontinent

The existence of Paleo-Mesoproterozoic supercontinent Columbia (aka Nuna) was established decades ago, but the position of North China Craton within Columbia is still highly debated due to the paucity of available high-quality paleomagnetic and reliable geological constraints. Precise geochronological dating of extensive Mesoproterozoic mafic dyke swarms in Western Shandong Province (also named the Luxi area), China reveals two phases of dyke emplacement at ~1.68 Ga and ~1.63 Ga. In this paper, we report new paleomagnetic and rock magnetic results obtained from approximate 160 samples (16 sites) collected from these two phases of mafic dyke swarms in the Luxi area with the aim of pinpointing the location of North China Craton within Columbia supercontinent in this time interval. Rock magnetic experiments confirm that either magnetite or titanomagnetite is the main magnetic carrier in these dykes. Stepwise thermal demagnetization revealed two paleomagnetic poles. For the ~1.63 Ga dykes, normal and reversed high-temperature remanent magnetization directions yield a mean direction (D/I) of 86.1°/53.5° (κ = 43.3, α95 = 7.9°, N = 9). These directions pass a reversal test and are interpreted as primary remanences. The corresponding paleomagnetic pole is calculated at 20.8°N, 182.5°E (κ = 28.3, A95 = 8.3°, N = 9). This pole passes the examination of secular variation of geomagnetic field (Deenen et al., 2011, 2014). It fulfills a Van der Voo (1990) value Q = 6 and is therefore suggested to be a ‘key’ pole demarcating the Precambrian North China Craton. For the ~1.68 Ga dykes, only the normal directions are isolated with a mean direction (D/I) of 89.1°/47.1° (κ = 35.0, α95 = 13.1°, N = 5) with a corresponding paleomagnetic pole of 17.8°N, 184.9°E (κ = 29.6, A95 = 14.3°, N = 5). This pole passes the examination of secular variation of geomagnetic field. Finally we select the ~1.63 Ga high-quantity paleomagnetic pole in order to depict a more detailed apparent pole wander path (APWP) to compare with the other major Precambrian cratons. Combined with other geological evidence, our reconstruction scenario supports the spatio-temporal connection between the Baltica, North Australian Craton and North China Craton.

Improvement of magnetic and cryogenic energy preservation performances in a feeding-power-free superconducting magnet system for maglevs

This work relates to improvement of magnetic and cryogenic energy preservation performances in an on-board high-temperature superconducting magnet system used in linear synchronous motors for ultrahigh speed maglevs. Since maglevs remove all the physical contacts to the ground, the wireless on-board feeding power is rather limited especially for superconducting subassemblies. And it has become one of the development bottlenecks. For the magnet system, realization of on-board feeding-power free is pivotal, which is regarding to two important energy conversions: electrical to magnetic energy by persistent-current mode of superconductivity, and latent heat to effective cooling (or cryogenic) energy by α-β phase transition of solid nitrogen (SN2) in the system. Improvements of the two energy conversions are the main work. Firstly, model and numerical approach of persistent-current mode are proposed, followed by simulation of SN2 cooling. Then performances of persistent-current mode and cryogenic energy preservation are reported. Energy conversion efficiency is also analyzed for a strategy to improve cooling performance. The strategy successfully extends cryogenic energy preservation time to 8.83 h and suppresses thermal non-uniformity to <0.1 K. The enhanced cooling performance is also reflected in a prolonged persistent-current mode lasting for 8.17 h. The work demonstrates the applicability of the magnet system.

Are Inorganic Single-Molecule Magnets a Possibility? A Theoretical Insight into Dysprosium Double-Deckers with Inorganic Ring Systems.

Computational studies of sandwich dysprosium double-decker complexes [Dy(L)2]+/3+ as candidates for single-ion magnets with several inorganic aromatic ring systems (P5-, N5-, B3N3H6, B3P3H6, B3S3H3) have been performed. The molecular structures were optimized with the TPSSh functional, and the ground state properties were investigated with the complete active space SCF method (CASSCF) complemented by the dynamic correlation dressed correction (DCD-CAS(2)) or NEVPT2. Besides the evaluation of the magnetic moment blocking barrier, the impact of the molecular vibration on the relaxation of magnetization was also inspected. We were able to make predictions about the performance of those molecules as single-molecule magnets, where estimated effective energy barrier, Ueff, values are as high as 1475 K in the case of [Dy(N5)2]-, which is the most anisotropic complex from our choice of studied compounds, making them a potentially very effective carbon-free alternative to organometallic double-decker dysprosocenium high-temperature single-molecule magnets.

HTS Dipole Prototype Magnet for NSLS X13A Endstation

This article reports the design, three-dimensional magnetostatic simulation results, coil fabrication, assembly, and low-temperature test results of a C-frame, iron-dominated high-temperature superconductor dipole magnet for ultra high vacuum magnetic-sensitive spectroscopy techniques at the National Synchrotron Light Source (NSLS) at Brookhaven National Laboratory. The magnet is required to provide fields up to ~1 T along two spatial directions. With an added capability to rotate about its vertical axis of symmetry, the magnet system is capable of delivering field along all three principal axes. The combination of this magnet and fast-switched, elliptically polarized soft X-rays produced by the NSLS elliptically polarized wiggler forms the basis for an excellent tool for polarization-sensitive studies of magnetic materials. The prototype magnet consists of a set of pancake coils fabricated from BSCCO tape reinforced with stainless steel. Those pancake coils are clamped in a low-carbon AISI 1006 grade steel pole and yoke assembly. For testing purposes, a cold He gas environment provided cooling the superconducting magnet to subtransition temperatures; for operation in an ultra high vacuum endstation environment, cooling can be provided by an external cryocooler. The low-temperature tests establish the safe-operating parameters needed to achieve the target magnetic field values. The measured magnetic field values are in close agreement with the magnetic simulation results, thereby confirming that the magnet design fulfills the performance requirements. The final section of this article lists some suggestions to improve the magnet performance.

High temperature spin reorientation, magnetization reversal and magnetocaloric effect in 50% Mn substituted polycrystalline ErFeO3

The structural, magnetic and magnetocaloric properties of 50% Mn substituted ErFeO3 are studied by X-ray diffraction, magnetization and specific heat measurements. ErFe0.5Mn0.5O3 crystallizes in an orthorhombic structure (Pbnm). DC magnetization and specific heat studies point to two magnetic transitions: (i) Fe3+/Mn3+ ordering, TN ~ 245 K and (ii) spin re-orientation transition, TSR ~ 218 K. Below TSR, ErFe0.5Mn0.5O3 exhibits a reduction in magnetization and coercivity which could be due to a Γ4-Γ1 magnetic transition. Interestingly, we have observed a negative magnetization in field cooled curves at lower temperatures under lower applied fields (<50 Oe) as a result of the polarization of paramagnetic Er3+ moments with the internal field created by Mn3+ ordering from the Mn-rich regions. A significant magnetic entropy change (-ΔSm) of 13.4 J/kg.K is also observed at 9.5 K for an applied field of 7 T.

Record fast-cycling accelerator magnet based on HTS conductor

Four decades ago development of high-current superconducting NbTi wire cables revolutionized the magnet technology for energy frontier accelerators, such as Tevatron, RHIC and LHC. The NbTi based magnets offered advantage of much higher fields B and much lower electric wall plug power consumption if operated at 4.5 K but relatively small ramping rates dB/dt << 0.1 T/s. The need for the accelerators of high average beam power and high repetition rates have initiated studies of fast ramping SC magnets, but it was found the AC losses in the low-temperature superconductors preclude obtaining the rates in the excess of (1- 4) T/s. Here we report the first application of high-temperature superconductor magnet technology with substantially lower AC losses and report record high ramping rates of 12 T/s achieved in a prototype dual-aperture accelerator magnet.

A New Concept of a Hybrid Trapped Field Magnet

This paper presents a new concept for a hybrid trapped field magnet made of second generation high-temperature super-conducting ring-shape magnet and HTS stack tapes. This hybrid trapped field magnet has the potential to provide a better magnetic field. This paper focuses on the magnetization properties of this new magnet. First, ultraviolet laser cutting technology was used to prepare the striated HTS tapes. Then both tradition method and “wind-and-flip” method were used to fabricate the ring-shape magnet. After that, basic features of the hybrid trapped field magnet, such as the maximum trapped field and decay rate were quantified by pulsed field magnetization (PFM) experiments. Due to the limitation of PFM method, a more cost-effective magnetization method based on thermal controlled persistent current switch (PCS) was investigated to achieve a higher trapped field. Finally, both numerical and experimental methods were used to analyze the working mechanism of the hybrid trapped field magnet. Conclusions of this paper show that the hybrid trapped field magnet is a potential concept to fabricate low cost, high performance magnets, and the “wind-and-flip” technology combined with PCS technique is a reliable way to improve the working performance as well as reduce the total cost magnetization facilities.

Test of Cryocooler-Cooled RE-123 Magnet on HIMAC Beam Line in S-Innovation Program

A cryocooler-cooled high-temperature superconducting magnet was constructed, and it was tested on the beam line of the heavy ion medial accelerator in Chiba (HIMAC). The magnet consists of a pair of four-stacked racetrack coils wound with RE-123 coated conductor that are plated with 41- μ m copper for protection. The magnet has a room temperature beam duct, at which 2.4 T of magnetic field is generated, whereas the maximum magnetic field to which coated conductors are exposed is approximately 4 T. The magnetic field in the beam duct was measured and calculated to examine its stability, which might have been affected by shielding currents in the coated conductors. On the beam line of the HIMAC, at first, the beam guiding by the magnet was demonstrated. The measured beam-guiding characteristics were compared with the beam tracking calculations. Next, a carbon ion beam was injected intentionally into the RE-123 coils of the magnet to simulate the incidents of uncontrolled beam injection into accelerator magnets. Prior to this test, the possible heat deposition to the coil by the beam injection was calculated, and the feasibility of quench protection using a dump resistor was studied through quench experiments using short pieces of the RE-123 coated conductors.

Field Stability Analysis of 25 T Cryogen-Free Superconducting Magnet and Upgrade Plans for 30 T System at HFLSM, IMR, Tohoku University

Magnetic field stability and hysteresis can be serious problems in a high-field high-temperature superconducting magnet, because of the large shielding current effect. Accordingly, the field stability of a 25 T cryogen-free superconducting magnet (25T-CSM) was investigated. This particular system can generate a central field of 24.6 T in a 52-mm room-temperature bore. It was found that the magnetic field relaxation rate of the 25T-CSM with a Bi2Sr2Ca2Cu3Oy (Bi2223) insert was due to the flux creep effect, and was small enough to allow nuclear magnetic resonance (NMR) experiments. Based on these experiences in the development of the 25T-CSM, primitive designs for a 30 T cryogen-free superconducting magnet (30T-CSM) were suggested based on upgrading the present Bi2223 insert to a REBa2Cu3Oy (RE123, RE: rare earth and Yttrium) insert incorporating two co-wound RE123 tapes. It was confirmed that the prototype test coil could be operated at 4.2 K under large electromagnetic stresses of up to 540 MPa without experiencing degradation.

Diffusive transport in a quasiperiodic Fibonacci chain: Absence of many-body localization at weak interactions

We study high-temperature magnetization transport in a many-body spin-1/2 chain with on-site quasiperiodic potential governed by the Fibonacci rule. In the absence of interactions it is known that the system is critical with the transport described by a continuously varying dynamical exponent (from ballistic to localized) as a function of the on-site potential strength. Upon introducing weak interactions, we find that an anomalous noninteracting dynamical exponent becomes diffusive for any potential strength. This is borne out by a boundary-driven Lindblad dynamics as well as unitary dynamics, with agreeing diffusion constants. This must be contrasted to random potential where transport is subdiffusive at such small interactions. Mean-field treatment of the dynamics for small U always slows down the non-interacting dynamics to subdiffusion, and is therefore unable to describe diffusion in an interacting quasiperiodic system. Finally, briefly exploring larger interactions we find a regime of interaction-induced subdiffusive dynamics, despite the on-site potential itself having no "rare-regions".