Low Magnetocrystalline Anisotropy Research Articles

Towards MnN as a replacement for IrMn

There is an urgent need to identify new antiferromagnetic materials that offer a replacement for IrMn alloys for room temperature and above applications. This is driven by the scarcity and high cost of Ir. Recently, MnN with {002} texture grown on a Ta seed layer has been proposed as a cost-effective alternative. However, two key issues need to be addressed before this material can be considered a realistic alternative to IrMn: thick layers of approximately 30 nm are required due to its relatively low magnetocrystalline anisotropy and nitrogen diffusion into the Ta layer at relatively low temperatures results in poor temperature performance. In this work, we show a potential pathway to overcome these issues. By using a W rather than a Ta seed layer, N diffusion is minimized, if not eliminated, at temperatures exceeding 300∘C\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$300\\,^{\\circ }\\hbox {C}$$\\end{document}. Furthermore, preferential {111} growth is achieved and a significantly enhanced anisotropy, 2.6·106erg/cm3\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$2.6 \\cdot 10^{6}\\,\\hbox {erg}/\\hbox {cm}^{3}$$\\end{document}, has been measured. This value is almost identical to that measured for 3D randomly oriented IrMn.

Probing the weak limit of magnetocrystalline anisotropy through a spin‒flop transition in the van der Waals antiferromagnet CrPS4

The influence of magnetocrystalline anisotropy (MCA) on antiferromagnetism is elucidated through the characterization of the spin‒flop transition. However, due to a lack of suitable candidates for investigation, a detailed understanding of the preservation of the spin‒flop transition in the presence of low MCA energy remains elusive. In this study, we introduce CrPS4, which is a two-dimensional van der Waals antiferromagnet, as an ideal system to explore the exceedingly weak limit of the thermally-evolved MCA energy. By employing a uniaxially anisotropic spin model and fitting it to the experimental magnetic properties, we quantify the MCA energy and identify the discernible spin configurations in different magnetic phases. Notably, even at the limit of extremely weak MCA, with a mere 0.12% of the interlayer antiferromagnetic exchange interaction at T = 33 K, which is slightly below the Néel temperature (TN) of 38 K, the spin‒flop transition remains intact. We further establish a direct correlation between the visualized spin arrangements and the progressive reversal of magnetic torque induced by rotating magnetic fields. This analysis reveals the essential role of MCA in antiferromagnetism, thus extending our understanding to previously undetected limits and providing valuable insights for the development of spin-processing functionalities based on van der Waals magnets.

Magnetic and magnetostrictive properties of Cu-doped cobalt ferrite

The Cu-doped cobalt ferrites CuxCo1-xFe2O4 (CCFO) were synthesized by a glycine-nitrate sol-gel auto-combustion method and investigated for structural, magnetic and magnetostrictive properties. X-ray diffraction and scanning electron microscopy analysis revealed the formation of single cubic-spinel phase for all the as-prepared powders, followed by the sintered samples with grain sizes around 2.5 µm. The variation in stoichiometric composition can be used to tailor magnetic and magnetostrictive properties. Saturation magnetization MS decreases from 84.8 to 60.4 emu/g with increasing Cu content from x = 0.0 to x = 0.50, accompanied with a reduction in coercivity HC from 1.21 to 0.41 kOe. The introduction Cu into CFO is conductive to the decline in magnetocrystalline anisotropy, giving rise to an improvement in magnetostriction at low applied fields. An optimized composition in the CuxCo1-xFe2O4 ferrites is found to be around x = 0.30, achieving good magnetoelastic properties, i.e., a large saturation magnetostriction (–λS ∼ 240 ppm), a high strain sensitivity (–dλ/dH ∼ 1.44 nm/A), as well as a low magnetocrystalline anisotropy coefficient (K1 ∼ 3.7 × 106 erg/cm3). The excellent magnetoelastic properties and the combination in a facile synthesis process for sintered polycrystalline ferrites, suggest promising prospects in magnetostriction applications.

High‑silicon electrical steel powders aimed for additive manufacturing

The Fe6.5Si soft magnetic alloy exhibits promising magnetic properties for energy applications, including near-zero magnetostriction, low magnetocrystalline anisotropy, and higher electrical resistivity than conventional electrical steels. However, its brittleness impedes industrial use. Recent advances in powder-based additive manufacturing show potential for processing high‑silicon electrical steels. This study focuses on the production cycle and properties of feedstock powder, which are crucial for such applications. Fe6.5Si alloy powders were produced via closed-coupled gas atomization. Comprehensive analysis covered mass balance, particle size distribution, powder flow, morphology, density, rheological properties, and thermal and magnetic behavior. Results suggest the feasibility of producing suitable Fe6.5Si alloy powder via gas atomization, enabling additive manufacturing of the next generation of medium/high-frequency electrical motors. The powder exhibited desirable characteristics within the size ranges applicable to laser powder bed fusion (20–75 μm) and direct energy deposition (75–106 μm), showing excellent flow behavior and morphological suitability for additive manufacturing.

Accelerating Nature: Induced Atomic Order in Equiatomic FeNi.

The production of locally atomically ordered FeNi (known by its meteoric mineral name, tetrataenite) is confirmed in bulk samples by simultaneous conversion X-ray and backscattered γ-ray 57 Fe Mössbauer spectroscopy. Up to 22 volume percent of the tetragonal tetrataenite phase is quantified in samples thermally treated under simultaneous magnetic- and stress-field conditions for a period of 6 weeks, with the remainder identified as the cubic FeNi alloy. In contrast, all precursor samples consist only of the cubic FeNi alloy. Data from the processed alloys are validated using Mössbauer parameters derived from natural meteoritic tetrataenite. The meteoritic tetrataenite exhibits a substantially higher degree of atomic order than do the processed samples, consistent with their low uniaxial magnetocrystalline anisotropy energy of ≈1 kJ·m-3 . These results suggest that targeted refinements to the processing conditions of FeNi will foster greater atomic order and increased magnetocrystalline anisotropy, leading to an enhanced magnetic energy product. These outcomes also suggest that deductions concerning paleomagnetic conditions of the solar system, as derived from meteoritic data, may warrant re-examination and re-evaluation. Additionally, this work strengthens the argument that tetrataenite may indeed become a member of the advanced permanent magnet portfolio, helping to meet rapidly escalating green energy imperatives.

CrP2Se6 monolayer: Two-dimensional intrinsic ferromagnetic half-metal with large magnetic anisotropy and high Curie temperature

Low Curie temperature (TC) and small magnetocrystalline anisotropy energy (MAE) are the main obstacle limiting the application of two-dimensional (2D) ferromagnetic (FM) materials. Here, by using first-principles calculations and Monte Carlo method, we predicted a 2D intrinsic FM CrP2Se6 monolayer with high TC and large MAE. The result shows that the TC of CrP2Se6 monolayer is about 440 K based on Monte Carlo simulations, and this monolayer possesses desired out-of-plane (z axis) easy magnetic axis with large MAE (∼1.2 meV/Cr). Interestingly, CrP2Se6 monolayer is intrinsically half-metallic with the spin filtering reaching 100 % and a wide spin gap of 3.09 eV under Heyd–Scuseria–Ernzerhof (HSE06) level. In addition, the dynamic, thermal, and mechanical stabilities of CrP2Se6 monolayer were confirmed by our phonon dispersion calculations, ab initio molecular dynamics simulations, and elastic constants, respectively. These outstanding magnetic properties make 2D CrP2Se6 monolayer a promising candidate for high efficiency spintronic devices.

Investigation of the electronic, magnetic, exchange interactions, and magnetocaloric properties in orthotitanate oxides RTiO3 (R = Er, Ho)

Strong correlated materials are emerging materials in low magnetocaloric cooling applications. The development of these fields necessitates materials with appealing magnetic, and magnetocaloric features. In this context, Density Functional Theory (DFT) combined with Monte Carlo simulations (MCs) are performed to comprehensively examine various physical, and magnetic features of the orthorhombic perovskite-type RTiO3. A metallic behavior of (Ho, Er)TiO3 has been found via the density of state using GGA+U approach. X-ray magnetic circular dichroism (XMCD) was carried out to identify the magnetic contributions of Ho, Er, and Ti atoms in HoTiO3, and ErTiO3 compounds. The spin-orbit coupling was added in our calculations to study and evaluate the magnetocrystalline anisotropies of RTiO3 with (R= Ho, Er). We noticed an easy magnetization axis along the b-direction for HoTiO3, and along the c-direction for ErTiO3. Low magnetocrystalline anisotropy energies were found compared to other perovskite oxides such as RVO3, and RMnO3 indicating that a weak rotating magnetocaloric effect (RMCE) is expected in (Ho, Er)TiO3. Moreover, the exchange coupling interactions were calculated using Ising model, the (Ti-Ti) interaction coupling is ferromagnetic, and larger than the other exchange interactions in (Ho, Er)TiO3. Furthermore, these exchange coupling interactions were utilized within the Heisenberg model for MCs, allowing us to understand the driving mechanisms underlying magnetocaloric and magnetic behaviors in (Ho, Er)TiO3.

An exotic uniaxial hexagonal ferrite with narrow self-biased ferrimagnetic resonance linewidths: Cu 18H hexaferrite

Traditional circulators utilize ferrites with low magnetocrystalline anisotropy driven by external magnetic bias fields. Hexagonal ferrites with a strong uniaxial anisotropy enable self-biased circulators, significantly reducing their volume, weight, and cost. Here, a unique uniaxial hexaferrite, Cu 18H hexaferrite, with narrow ferrimagnetic resonance (FMR) linewidth at zero magnetic bias field is reported. The temperature-dependent magnetic hysteresis loops show a significant decrease in coercivity from cryogenic to room temperature, indicating a transition from the hard to soft magnetic state. The crystallographic texture ensures a squareness ratio greater than 0.65 and leads to a strong internal bias field induced by the aligned easy-magnetization axes. Owing to the highly dense and oriented crystallites, the zero-field FMR exhibits excellent linewidths of ∼270–320 Oe, which are lower than those of most hexaferrites reported at the Ka-band. These results reveal the great potential of Cu 18H hexaferrite as a low-loss microwave ferrite used for self-biased circulators.

Emergent Magnonic Materials: Challenges and Opportunities.

Advances in information technology are hindered by energy dissipation from Joule losses associated with charge transport. In contrast, the process of information based on spin waves propagation (magnons) in magnetic materials is dissipationless. Low damping of spin wave excitations is essential to control the propagation length of magnons. Ferrimagnetic Y3Fe5O12 garnets (YIG) exhibit the lowest magnetic damping constants. However, to attain the lowest damping constant, epitaxial growth of YIG on single crystal substrates of Gd3Ga5O12 at elevated temperatures is required, which hinders their CMOS integration in electronic devices. Furthermore, their low saturation magnetization and magnetocrystalline anisotropy are challenging for nanoscale device applications. In the search for alternative material systems, polycrystalline ferromagnetic Co25Fe75 alloy films and ferrimagnetic spinel ferrites, such as MgAl0.5Fe1.5O4 (MAFO), have emerged as potential candidates. Their damping constants are comparable, although they are at least one order of magnitude higher than YIG's. However, Co25Fe75 alloy thin film growth is CMOS compatible, and its magnon diffusion length is 20× longer than in MAFO. In addition, MAFO requires epitaxial growth on lattice-matched MgAl2O4 substrates. We discuss the material properties that control the Gilbert damping constant in CoxFe1-x alloys and MAFO and conclude that CoxFe1-x alloy thin films bring us closer to the realization of the exploitation of spin waves for magnonics.

Stoichiometry and spin-orbit coupling in Mn–Pt–Sn Heusler compound

This study uses density functional theory implemented in the Vienna ab initio simulation package (VASP) software to examine the impact of spin-orbit coupling (SOC) on the electronic and magnetic properties of the inverse tetragonal Heusler compound Mn1.5PtSn with various spin orientations. Regardless of the presence or absence of SOC, it has been found that the ferrimagnetic configuration is more stable at the ground state than the ferromagnetic and antiferromagnetic one. The SOC influences the ground state energy of the compounds. The exchange coupling parameters, density of states, bandstructure plots, charge density distribution, and Bader charge analysis help in understanding the magnetic and electronic properties of the system. The high spin-polarization in the vicinity of the Fermi level and the low magnetocrystalline anisotropy energy obtained for the stable ferrimagnetic configuration opens up the possibility of tuning the system for spin-transfer-torque based device applications, like magnetic recording heads.

Development of Fe-based diluted nanocrystalline alloy by substituting C for P in FeSiBCCu system

Here, an Fe85.7Si1B10C1P2Cu0.3 diluted nanocrystalline alloy exhibiting relatively high Bs of 1.69 T and low Hc of 2.58 A/m is successfully developed. In addition, the effects of substituting C with P on the thermal behavior, magnetic properties, microstructure, and magnetic domains of Fe85.7Si1B10C3−xPxCu0.3 (x = 0, 1, 2, and 3 at%) amorphous alloys are investigated. It is found that the addition of P not only improves glass forming ability, but also enhances thermal stability of the amorphous alloy. Furthermore, the suitable P addition can also optimize the soft magnetic properties under heat treatment. For the Fe85.7Si1B10C1P2Cu0.3 alloy, the improved Bs is due to the formation of bcc-Fe crystals and the lowest Hc is caused by the low magneto-crystalline anisotropy, which are both induced by the construction diluted nanocrystalline structure. The formation of this unique microstructure is due to the competition between stabilization effect on amorphous phase of higher crystallization activation energy and the facilitation effect on the formation of bcc-Fe crystal by atomic-scale preexisting crystal-like clusters.

Application of electroplated Ni–Fe thick film to magnetostrictive material in vibration power generator

Ni100−xFex (at. %) films of about 37 μm thickness are electroplated on Cu base plates of 50 mm length, 10 mm width, and 300 μm thickness by varying the composition from x = 0 to 99. They are applied to cantilevers in magnetostrictive vibration power generators. The influences of magnetic and magnetostrictive properties of electroplated film on the vibration power generation property are systematically investigated. The films with x = 41–65 show low coercivities of about 4 Oe reflecting the low magnetocrystalline anisotropy constants. Large negative magnetostriction is recognized for the films with x = 0–14, whereas large positive magnetostriction is observed for the films with x = 57–80. The cantilevers are vibrated at the respective resonance frequencies of about 105–115 Hz and with the acceleration of 1.5 G while applying the bias magnetic field in a range of 0–300 Oe along the length direction. The output voltages are detected by using a coil with 8000 turns. Peak voltages higher than 1 V are obtained for the films with x = 61–65 whose coercivities are low and magnetostrictions are large. The present study has shown that an Ni–Fe film not only with large magnetostriction but also with low magnetic anisotropy constant is useful as the magnetostrictive material in vibration power generator.

The development of rare-earth combined Fe-based magnetic nanocomposites for use in biological theranostics.

Iron (Fe)-based nanoparticles (NPs) represented by Fe3O4 exhibit attractive properties, such as high saturation magnetization, low magneto-crystalline anisotropy, and good biocompatibility, and are useful as magnetic resonance imaging (MRI) contrast agents. However, the existence of artifacts makes the single magnetic resonance imaging mode lack accuracy in tumor diagnosis. To overcome this limitation, a strategy where rare-earth elements are combined with Fe-based NPs is applied. Rare earth is the general name of Sc, Y, and elements with unique 4f electronic configurations. Some rare-earth elements like Gd and Lu exhibit magnetic properties due to unpaired electrons, while some, like Er and Ho, fluoresce under excitation ascribed to the electron transition at intermediate energy levels. In this manuscript, attention is focused on multimodal nanomaterials composed of rare-earth elements and Fe-based NPs. We provide an overview of the synthetic routes and current biomedical application of the nanocomposites that show potential for precise diagnosis and efficient treatment of cancers.

Large magnetostriction over a wide temperature range in a Nd0.2TbxDy0.8−xFe1.93 Laves compound

Rare-earth-based magnetostrictive alloys exhibit giant low-field magnetostriction due to anisotropy compensation at specific compositions and temperatures. However, the normally strong temperature dependency of magnetostriction is a common issue that limits its application temperature range. Here, we found that low-field magnetostrictive properties were optimized over a wide temperature range in a low-cost Nd0.2TbxDy0.8−xFe1.93 system. A 140 K temperature window with λ ≥ 750 ppm at 2 kOe was achieved in the Nd0.2Tb0.3Dy0.5Fe1.93 compound, which is about 2.7 times wider than that in the well-known Terfenol-D composition. The construction of the Nd0.2TbxDy0.8−xFe1.93 spin reorientation phase diagram revealed a slightly steeper slope of the phase boundary than that of the Nd-free system. Further analysis shows that a steep phase boundary allows the optimized composition to maintain low magnetocrystalline anisotropy and, thus, large low-field magnetostriction in a wide temperature range. The findings in this work may provide a route for designing wide-temperature-operating magnetostrictive materials by searching the phase boundary with a steep slope.

Real-Time Observation of Magnetic Domain Structure Changes with Increasing Temperature for Z-Type Hexagonal Ferrite.

Z-type hexagonal ferrites have recently received attention for their room-temperature magnetoelectric (ME), which is activated when the temperature at which the transverse-conical spin-state transitions to a ferrimagnetic state is increased. The changes in the magnetic domain structure at the transition have been well-documented; however, they are still not understood in detail. In the present study, Lorentz transmission electron microscopy (TEM) analysis combined with an in situ heating experiment was conducted to demonstrate the shift in magnetic domain structure during the transition from the transverse-conical spin arrangement to a ferrimagnetic spin order. The dynamics of the magnetic domain structure changes with the increasing temperature were acquired in real-time. At 490 K, the magnetization transition from the transverse-conical spin state to the ferromagnetic state was demonstrated. Cross-tie domain walls formed during the magnetic transition process. The increased effect of the demagnetizing field applied to the 180° magnetic domains was caused by a lower magnetocrystalline anisotropy (MCA) at the easy axis of magnetization.

Effects of particle morphology and magnetocrystalline anisotropy on < 111 > orientation and magnetostriction of sintered Tb-Dy-Fe/DyCu compacts

Sintered Tb-Dy-Fe materials prepared by the compression molding method have higher relative density and energy density than powder-bonded composites. However, due to the low magnetocrystalline anisotropy and the cubic symmetry of the Laves structure, the orientation degree of sintered materials is relatively low and not beneficial for obtaining large magnetostriction. We prepared the sintered Tb-Dy-Fe/DyCu compacts with preferred <111 > orientation by applying magnetically oriented powder metallurgy. The dependence of orientation degree and magnetostriction of oriented Tb-Dy-Fe/DyCu sintered compacts on different particle morphology and Tb/Dy ratios were studied. The oriented Tb-Dy-Fe/DyCu sintered compacts prepared from the milled single crystal Tb-Dy-Fe powders gained a higher <111 > orientation due to the small rotational resistance when magnetic particles move in a magnetic field, achieving improved magnetostriction. Magnetocrystalline anisotropy which determines the rotational torque caused by the magnetic field is one of the important factors affecting the rotation behavior of magnetic particles in a magnetic field. We designed Tb-Dy-Fe alloys with different Tb/Dy ratios which have different magnetocrystalline anisotropy, and prepared the sintered Tb-Dy-Fe/DyCu compacts under the same process parameters. The magnetocrystalline anisotropy constant K1 of TbxDy1-xFe1.95 (x = 0.27, 0.30, 0.33, 0.50) alloys increased from 0.66 × 106 J/m3 to 3.85 × 106 J/m3 by raising the Tb/Dy ratios, and the <111 > orientation degree of sintered Tb-Dy-Fe/DyCu compacts was promoted simultaneously. The oriented Tb0.33Dy0.67Fe1.95/DyCu sintered compact achieved the highest <111 > orientation degree of 56.6%, resulting in the largest magnetostriction of 1326 ppm and the d33 peak value of 6.81 nm/A.

Recent Advances in Magnetostrictive Tb-Dy-Fe Alloys

As giant magnetostrictive materials with low magnetocrystalline anisotropy, Tb-Dy-Fe alloys are widely used in transducers, actuators and sensors due to the effective conversion between magnetic energy and mechanical energy (or acoustic energy). However, the intrinsic brittleness of intermetallic compounds leads to their poor machinability and makes them prone to fracture, which limits their practical applications. Recently, the addition of a fourth element to Tb-Dy-Fe alloys, such as Ho, Pr, Co, Nb, Cu and Ti, has been studied to improve their magnetostrictive and mechanical properties. This review starts with a brief introduction to the characteristics of Tb-Dy-Fe alloys and then focuses on the research progress in recent years. First, studies on the crystal growth mechanism in directional solidification, process improvement by introducing a strong magnetic field and the effects of substitute elements are described. Then, meaningful progress in mechanical properties, composite materials, the structural origin of magnetostriction based on ferromagnetic MPB theory and sensor applications are summarized. Furthermore, sintered composite materials based on the reconstruction of the grain boundary phase also provide new ideas for the development of magnetostrictive materials with excellent comprehensive properties, including high magnetostriction, high mechanical properties, high corrosion resistance and high resistivity. Finally, future prospects are presented. This review will be helpful for the design of novel magnetostrictive Tb-Dy-Fe alloys, the improvement of magnetostrictive and mechanical properties and the understanding of magnetostriction mechanisms.

The new stable phases of Fe2Pd crystal alloy and their properties

This work presents a combination of particle swarm optimization crystal structure search method and first-principles calculations to investigate new stable crystal structures of Fe2Pd. Three structurally stable tetragonal phases (with space groups I4/mmm, P4/mmm, P4/nmm) and a structurally stable cubic phase (C15 Laves phase (Fd3¯m)) are predicted at 0 GPa. The enthalpy of formation reveals that these four phases are thermodynamically stable in the ferromagnetic state, and the tetragonal P4/nmm phase has the highest stability. Calculated phonon spectra indicates that the remaining three predicted structures are dynamically stable except for I4/mmm structure. From the elastic constant, all of the predicted structures are mechanically stable phases. Among these studied structures, the three tetragonal phases with similar values of bulk modulus have high uniaxial magneto-crystalline anisotropy, high thermal expansion coefficient, large bulk modulus, and good ductility. However, the cubic Fd3¯m phase is characterized by low magneto-crystalline anisotropy, small thermal expansion coefficient, high shear and Young’s modulus, and brittleness. Finally, the high-pressure stability of these four structures is investigated. The theoretical prediction indicates a structural transition from tetragonal P4/nmm phase to ductile Fd3¯m structure at 26.8 GPa, while the I4/mmm is the most stable above 80 GPa.

Crystalline orientation-related magnetic anisotropy in transition metal dichalcogenides 1T′-MoTe2/Co heterostructures

The semimetal transition metal dichalcogenides (TMD) MoTe2 have attracted extensive research interests in Spintronics. The understanding of the magnetic properties of MoTe2/Ferromagnetic (FM) heterostructures is critical to the design of novel Spintronics-based devices. However, there is lack of research on the magnetic anisotropy of the semimetal TMD/FM. Here, we demonstrate the in-plane crystalline orientation-related magnetic properties of MoTe2/Co to clarify the relationship between the crystalline orientation and the magnetic anisotropy. We carried out the studies of crystalline orientation-related magnetic anisotropy in 1T′-MoTe2/Co heterostructures from both experiments and first-principles calculations. Our results show that for Co with different thicknesses, the easy axis of Co film is along the b-axis of MoTe2 with uniaxial magnetic anisotropy. It is also consistent with the results of our theoretical results. When Co film thickness increases, the magnetocrystalline anisotropy (MCA) oscillates around a constant value with a lower MCA along the out-of-plane direction. Meanwhile, the demagnetization energy which increases linearly as a function of Co thickness, which would make the easy axis in-plane. Our work may give a fundamental inspiration for Spintronics based devices with semi-metallic TMDs/ferromagnetic materials.

C-axis oriented polycrystalline BaNi2GdxFe16-xO27 (x = 0.0, 0.1, 0.2, 0.3, 0.4 and 0.5) for the application of self-biased circulator at K band

The grains of oriented W-type hexaferrite BaNi2GdxFe16-xO27 (BaW) where x = 0.0, 0.1, 0.2, 0.3, 0.4 and 0.5 grew uniformly along their c-axis perpendicular to the sample plane, which meant high remanence ratio of BaW. When Gd3+ substitution content was x = 0.0, the corresponding remanence ratio reached as high as 0.90. When x = 0.2, the oriented BaW simultaneously possessed high saturation magnetization (Ms= 58.36 emu/g), high coercivity (Hc = 1527 Oe), high remanence ratio (Mr/Ms = 0.85), relatively low magnetocrystalline anisotropy field (Ha = 10,253 Oe) and low ferromagnetic resonance linewidth (ΔH = 624 Oe). These characteristics indicated the material was suitable for the design of self-biased circulator operated at K band. Based on the BaW material, self-biased double Y-junction microstrip circulator was designed and realized well circulatory function at K band.