Ferromagnetic Hysteresis Loops Research Articles

A study on BaTiO3 – NiFe2O4 composite; microstructure, multiferroic and magnetodielectric properties

The lead-free x NiFe2O4 – (1-x) BaTiO3 (x = 0, 0.05, 0.1, 0.15) multiferroic composites were prepared via the solid-state sintering technique. Microstructure, multiferroic, and magnetodielectric properties of composites were investigated. According to the XRD data (from x = 5 to 15 wt%), the tetragonality factor (cT/aT) and unit cell volume of the BaTiO3 (BTO) crystal system diminished. Based on SEM images, ferromagnetic NiFe2O4 (NFO) grains are uniformly dispersed in the ferroelectric BTO matrix without additional reaction in the interfaces of two phases. The highest values of dielectric (dielectric constant (εr) ∼ 1905 and dielectric loss factor (tan δ) ∼ 0.049) and ferroelectric properties (saturation polarization (PS) ∼ 13 μC/cm2 and remnant polarization (Pr) ∼ 10 μC/cm2) are attained for x = 5 wt% due to the lowest NFO (non-ferroelectric) concentration. Also, with increasing ferrite concentration (up to 15 wt%), the ferroelectric properties of the composites show a gradual decrease. The saturation magnetization (MS) values rise due to increasing ferrite concentration (from 2 to 5 emu/g for x = 5 to 15 wt%). Moreover, coercivity (HC) drops from 150 to 110 Oe. The simultaneous observation of the ferroelectric and ferromagnetic characteristic hysteresis loops confirmed the multiferroic effect for x = 5, 10, and 15 wt%. The highest magnetodielectric constant (3 %) is obtained for x = 15 wt% multiferroic composite at the applied magnetic field of 6 kOe.

Intrinsic origin of room temperature ferromagnetic ordering in (In0.97-xCoxMg0.03)2O3 thin films

The (In0.97-xCoxMg0.03)2O3 films with different Co concentration are prepared using RF magnetron sputtering. The XRD and XPS measurements show that the films are highly oriented and both Co and Mg elements present valence state of +2. The EXAFS spectra show that only substitutional Co ions exist in the film with x = 0.02. However, the films with higher Co concentration (x > 0.02) form separate phases of substitutional Co and metallic Co clusters. All the films exhibit n-type conductivity and the carrier concentration firstly decreases and then increases with Co doping. The transport mechanisms are dominated using Mott variable range hopping at low temperature and Hard bandgap hopping at high temperature. The Co dopant can effectively alter the MR characters, which undergoes a clear transition from negative MR to positive MR. All the films exhibit room temperature ferromagnetic hysteresis loop. Clear increase of ferromagnetic hysteresis loop and saturation magnetic moment are observed due to the incorporation of Co ions. The ferromagnetism is ascribed to oxygen vacancies-induced bound magnetic polarizations. The relative percentage of substitutional Co ions decrease with Co doping, which leads to the decreasing of number of bound magnetic polarons induced by oxygen vacancies, and then weaken the Ms.

Critical characteristics of spin − 1/2 four-leg nanotube: Monte Carlo Simulation

In this study, we aim to investigate theoretically the critical characteristics of spin −1/2 four-leg nanotube for the nanotechnology applications. The Ising model simulated by Monte Carlo simulation is adopted with the first exchange coupling J , the second exchange coupling between the second nearest neighbor atomic spins J ′ and the transverse exchange coupling J z , and the external magnetic field h as parameters. Herein, we examine the local properties of spin −1/2 four-leg nanotube by analyzing the magnetization, susceptibility and hysteresis loop behavior as function of J ′ , J Z and h . The obtained results show that the isotropic ‐ 1 / 2 four-leg nanotube Ising model presents critical behavior at ferromagnetic to paramagnetic phase transition where the Curie temperature T C increases according to vertical and second nearest neighbor exchange coupling. Furthermore, under external magnetic field, the magnetization keeps the second order transition and the magnetic susceptibility declines with the increase of applied external magnetic field value. In addition to that, we have found single ferromagnetic hysteresis loops, for which the shape increases by increasing the second nearest neighbor exchange coupling when T = J . Finally, the critical temperature shows perfect mirror symmetry relative to the vertical and increases with the second nearest neighbor exchange coupling.

Structural characterization, electrical and magnetic properties of (In0.97-xFexMg0.03)2O3 films

Structural, electrical, and magnetic properties of (In0.97-xFexMg0.03)2O3 films with different Fe concentration are investigated. The doped Fe ions replace the In1 sites of In2O3 lattice with the mixed-valence of +2 and +3 states and form FeIn1+2VO complex based on the real-space multiple-scattering simulation. The room temperature ferromagnetic hysteresis loop of Fe/Mg co-doped In2O3 films shows ferromagnetic ordering with coercivity Hc of about 150-300 Oe. Obvious increase of ferromagnetic hysteresis loop and saturation magnetic moment with a maximum value of 8.45 emu/cm3 (x = 0.08) are observed due to the more incorporation of Fe ions. All the films exhibit n-type conductive behavior, which are mainly dominated by Mott variable range hopping with strong localization of carriers. Interestingly, the contribution of positive and negative magnetoresistance (MR) strongly correlates with Fe dopant and temperature. It can conclude that the FeIn1+2VO complex based on bound magnetic polaron model plays a key role for achieving the intrinsic ferromagnetism.

Sputter epitaxy and characterization of manganese-doped indium tin oxide films with different crystallographic orientations

Epitaxial Mn-doped indium tin oxide (ITO) films were deposited on single-crystal yttria stabilized zirconia (YSZ) substrates with (111), (110), and (100) crystal plane orientations using RF magnetron sputtering. The epitaxial relationship between the Mn-doped ITO films and the YSZ substrates was studied using x-ray diffraction (XRD) patterns in the ω–2θ scan mode and XRD pole figures. The Mn-doped ITO films on the YSZ(111) and YSZ(110) substrates exhibited a higher degree of crystallinity than the film on the YSZ(100) substrate as per the x-ray rocking curves. Fluctuations in the crystalline alignment were found to significantly influence the electrical properties of Mn-doped ITO films. Ferromagnetic hysteresis loops were observed at room temperature for all the epitaxial Mn-doped ITO films, irrespective of their crystallographic orientation. The magnetic properties of the epitaxial Mn-doped ITO films suggest that a combination of delocalized charge carrier-mediated interaction and bound magnetic polaron-driven interaction is required to explain the origin of ferromagnetism in these films. The Mn-doped ITO film on the YSZ(111) substrate exhibited the most desirable characteristics in terms of crystallinity, surface smoothness, electrical conductivity, and magnetic properties.

Electrical, Dielectric, and Magnetic Characteristics of (BiBa)(FeMn2)O8

A new compound of chemical formula (BiBa)(FeMn2)O8 is prepared by a solid‐state reaction method. X‐ray structural studies confirm orthorhombic unit cell of the compound. Room‐temperature magnetic data display ferromagnetic hysteresis loop with high value of effective magnetic moments. The dependence of dielectric constant, loss tangent, impedance, and the conductivity at different frequencies (1 kHz−1 MHz) are measured using LCR meter on rise of temperature from room temperature to 500 °C. The dielectric constant increases on rise of temperature due to Maxell–Wagner polarization, and the loss tangent displays similar behavior. A low value of loss tangent is obtained at higher frequencies, which paves the way for the application of the compound in high‐frequency devices. The real impedance of the compound decreases indicating NTCR (negative temperature coefficient of resistance) behavior, and the imaginary impedance displays relaxor behavior. The Nyquist plot fits to a series combination of two RQC circuits ((RQC)(RQC)) and indicates the presence of non‐Debye relaxation. The frequency variation of conductivity obeys Jonscher's power law and reveals different conduction mechanisms in grain and grain boundary regions.

High-mobility spin-polarized two-dimensional electron gas at the interface of EuTiO3/SrTiO3 heterostructures

Spin polarization of two-dimensional electron gas (2DEG) at the interface of EuTiO3/SrTiO3(STO) heterostructures has been theoretical predicted and experimentally observed via x-ray magnetic circular dichroism and polarized x-ray absorption spectroscopy, which, however, is lack of magnetotransport evidence. Here, we report the fabrication of high-quality EuTiO3/STO heterostructures by depositing antiferromagnetic insulating EuTiO3 thin films onto STO substrates. Shubnikov-de Haas oscillation, Hall, and magnetoresistance (MR) measurements show that the interface is not only highly conducting, with electron mobility up to cm2V−1s−1 at 1.8 K, but also shows low-field hysteretic MR effects. MR of ∼9% is observed at 1.8 K and 20 Oe, which is one order of magnitude higher than those observed in other spin-polarized 2DEG oxide systems. Moreover, the heterostructures show ferromagnetic hysteresis loops. These results demonstrate that the high-mobility 2DEG is spin polarized, whose origin is attributed to the interfacial Ti3+-3d states due to oxygen deficiency and the exchange interactions between interfacial Eu spins and itinerant Ti-3d electrons.

Cr3+ doping-controlled magnetic and dielectric properties of polycrystalline Y-type BaSrCo2Fe11-xCrxAlO22 hexaferrite

The trend towards multifunctionality and integrating electronic devices has led to the exploration of Y-type hexaferrite with excellent magnetic and dielectric properties. The Y-type hexaferrite BaSrCo2Fe11-xCrxAlO22 (0.0 ≤ x ≤ 0.5, with step of 0.1) ceramics have been prepared by conventional solid state reaction route. The phase structure, microscopic morphology, magnetic and dielectric properties of Y-type hexaferrite with chromium substitution are studied in detail. The analysis of XRD, SEM and EDS reveals that the lattice parameters and grain size decrease with the increase of Cr content. XPS results show the coexistence of Fe2+ and Fe3+. All samples exhibit well-defined ferromagnetic hysteresis loops at room temperature and the Cr3+ doping enhances the saturation magnetization and coercivity. The dielectric constants for all samples are found in the range of 10–15 and the dielectric loss is less than 0.02 at high frequency. The resistivity demonstrates that the samples possess high insulating nature with all above 2 × 109 Ω·cm, with a maximum value of 9.5 × 109 Ω·cm for x = 0.2. These results reveal that Cr3+ doped Y type hexaferrite could have potential applications in multifunctional electronic devices.

High dielectric-energy storage and ferromagnetic-superparamagnetic properties: tetra-doping CuO nanocompositions

Tetra-doping by (Mn, Fe, Co, Ni) ions strongly boosted the room temperature dielectric constant and the ferromagnetic-superparamagnetic characteristics of monoclinic CuO structure. In this study, undoped CuO, Cu0.98Mn0.005Fe0.005Co0.005Ni0.005O, Cu0.96Mn0.01Fe0.01Co0.01Ni0.01O and Cu0.94Mn0.015Fe0.015Co0.015Ni0.015O nanocompositions were synthesized through coprecipitation technique. The crystal structure analysis verified that all samples have a pure single phase, corresponding to monoclinic CuO structure. The substitution of Cu2+-sites into CuO lattice by Mn2+, Fe2+/3+, Co2+ and Ni2+ ions has been deduced from the expansions of lattice constant, shifts of XRD diffraction peaks and band gap energy alteration. The additions of (Mn, Fe, Co, Ni) ions lead to the formation of homogenous distributed very fine spherical nanoparticles, especially at large concentrations of dopants (Cu0.94Mn0.015Fe0.015Co0.015Ni0.015O sample). The tetra-doping by (Mn, Fe, Co, Ni) ions reduced the intensity of the diffuse reflectance alongside red shifted the absorption edge and the band gap energy of monoclinic CuO structure. Cu0.98Mn0.005Fe0.005Co0.005Ni0.005O exhibits a high relative permittivity value of 6096 at low frequency of 42 Hz with small dielectric loss tangent (tan δ) compared to pure one. The tetra-doping by (Mn, Fe, Co, Ni) dopants induced excellent intrinsic ferromagnetic and superparamagnetic hysteresis loops into monoclinic CuO structure with full saturation loops shape and variable coercivity values.

On the Paramagnetic-Like Susceptibility Peaks at Zero Magnetic Field in hbox{WSe}_{2-x}hbox{Te}_{x} Single Crystals

A weakly temperature-dependent paramagnetic-like susceptibility peak at zero magnetic field is observed in hbox{WSe}_{2-x}hbox{Te}_{x} with only marginal amount of ferromagnetic impurities. The ferromagnetic hysteresis loop and the magnetic moment splitting between zero-field-cooled and field-cooled processes indicate ferromagnetism in the samples. The paramagnetic-like susceptibility peak height is proportional to the remanent magnetic moment of hysteresis loops. High-resolution transmission electron microscope image supports that the observed ferromagnetic feature originates from lattice distortion. These results imply that the weakly temperature-dependent paramagnetic-like susceptibility peak originates from weak lattice distortion and/or superparamagnetism.

The effect of hydrogen pressure on magnetic properties of Zr2(Co0.5Fe0.2Ni0.2V0.1) alloy

The influence of hydrogen pressure on the magnetic and microstructure properties of Zr2(Co0.5Fe0.2Ni0.2V0.1) alloy was investigated in low and high hydrogen pressure. XRD and Rietveld refinement analysis of the as-cast alloy shows a multiphase crystal structure, mainly consisting of the C16 tetragonal phase. Mössbauer spectra and magnetic measurements confirmed a formation of interacting superparamagnetic clusters within a paramagnetic matrix. A typical spin glass-like transition was observed at blocking temperature below 30 K. Hydrogenation shows a significant increase in the magnetic properties. Under low hydrogen pressure (hydrogen content ∼19 mmol/gr), a ferromagnetic hysteresis loop was observed without any significant change in the crystal structure, indicating that exchange interaction between clusters increased markedly by hydrogenation. In high hydrogen pressure (hydrogen content ∼42 mmol/gr), the disproportionation reaction altered both the crystal structure and the magnetic property of the alloy. The presence of at least two interacting superparamagnetic phases within the paramagnetic matrix can be represented by fitting the M(H) data to the theoretical model. This study discusses a complex case of magnetic clusters embedded in a paramagnetic matrix and is a good example of drastic changes of magnetic properties by hydrogenation.

New nonmagnetic aliovalent dopants (Li+, Cu2+, In3+ and Ti4+): Optical and strong intrinsic room temperature ferromagnetism of perovskite BaSnO3

Nonmagnetic Li+, Cu2+, In3+ and Ti4+ ions were employed to induce robust room temperature ferromagnetism in perovskite BaSnO3 for advanced spintronics applications. New BaSn0.96M0.04O3 (M = Li+, Cu2+, In3+ and Ti4+) compositions were synthesized by modified Pechini method. In all compositions, single phase of cubic BaSnO3 was detected in the XRD patterns without any impurities. The FTIR spectra displayed the distinctive vibrational absorption band of BaSnO3 and verified the absence of any impurities. The SEM images evidently showed a decrement of grain size alongside morphological changes for doped BaSnO3 compositions compared to the pure one. The band gap energy of BaSnO3 was considerably influenced by the incorporation of Li+, Cu2+, In3+ and Ti4+ dopants. BaSn0.96Cu0.04O3 sample exhibited the highest refractive index value and the minimum value was obtained for BaSn0.96Ti0.04O3. Remarkably, at equal concentration two of the used nonmagnetic elements showed the ability to induce room temperature ferromagnetism in BaSnO3 lattice. Herein, BaSn0.96Cu0.04O3 exhibits a robust and symmetrical ferromagnetic hysteresis loop with complete saturation magnetization (Ms) of 0.158 emu/g and coercivity (Hc) of 42 Oe. BaSn0.96Ti0.04O3 composition revealed a ferromagnetic behavior within magnetic field of± 5000 Oe and the trend was reversed for higher values to show a diamagnetic performance. The interaction between the 3d orbitals of Cu2+ (3d9) or Ti4+ (d0) with the trapped electrons in the oxygen vacancies encourage a ferromagnetic coupling in BaSnO3 structure. The outer shell orbitals of Cu2+ and Ti4+ dopants and the oxygen vacancies seem to play a significant role in the magnetic properties.

Effect of Cobalt Substitution on the Structural and Magnetic Properties of Bismuth Ferrite Powders

BiFeO3 (BFO) is a multiferroic material with excellent ferroelectric properties but with poor magnetic behavior. Therefore, we focused principally on the enhancement of the magnetic order of BFO. These multiferroic properties make BFO an excellent candidate for magnetoelectric devices at room temperature. Pure and Co-BiFeO3 powders were successfully synthesized via the sol–gel method at 700 °C. The effect of Co substitution on the corresponding structural and magnetic properties of BFO was studied. X-ray diffraction and Fourier Transform Infrared Spectroscopy measurements confirmed the rhombohedral perovskite structure in all samples. A secondary phase of CoFe2O4 (CFO) was detected for 9, 10, and 15% of Co doping. The scanning electron microscopy images of the Co-BFO particles showed a reduction in the particle size compared to the pure BFO powders. Vibrating sample magnetometry measurements evidenced the ferromagnetic hysteresis loop for the Co-BFO powders with values of saturation magnetization of 4.1 emu/g and a coercivity of 1083 Oe for 15% of Co doping. In this work, we report impurity free samples with notable magnetic properties at the same time, which is a difficult challenge in bismuth ferrite synthesis. This is the first step for later applications in future technology.

Effects of Fe Dopant on Structural, Optical and Electrical Properties of NiTiO3 Materials

In this study, the effects of Fe dopant on the structural, optical, and electrical properties of NiTiO3 materials prepared by sol-gel method were investigated. The prepared powders were investigated through X-ray diffraction, Raman scattering, scanning electron microscope, UV-visible absorption, vibrating sample magnetometer, electrical measurement to explore the structural, ferromagnetic, and electrical properties. The single-phase Ni1-xFexTiO3 (x = 0, 0.05 and 0.10) materials were obtained. Doping of Fe into NiTiO3 lead to the decreasing of lattice parameter and increased the particle size compared to the undoped sample. Ferroelectric and ferromagnetic properties of all Fe-doped NiTiO3 ceramics have been investigated at room temperature. The ferromagnetic hysteresis loop of the Fe-doped NiTiO3 sample at room temperature is due to the formation of oxygen vacancies and their associated exchange interaction. Ferroelectric properties of Fe doped samples were decreased with the increase of Fe concentration. This can be due to the Fe dopant into NiTiO3 material. The Fe dopant caused to increase the conductivity of NiTiO3 sample which resulted in a decrease in ferroelectric parameters.

Role of Sr+2 ions substitution on structural and multiferroic properties of BiFeO3 nanoparticles

The multiferroic nanoparticles Bi1−xSrxFeO3 (BiSrFeO3) were prepared by performing ceramic method; (0.10 ≤ x ≤ 0.25). Nanostructure and multiferroic properties of the synthesized materials were studied. BiSrFeO3 is a single-phase hexagonal-rhombohedral crystal structure as evidenced by X-ray diffraction (XRD) patterns. It has been found that all BiSrFeO3 nanoparticles are ferroelectric materials. The ferroelectric properties of BiFeO3 changed when Sr2+ ions were substituted. At x = 0.25 mol%, Sr2+ ions lead to the magnetization development of BiFeO3. At room temperature, the remnant magnetization increased from its initial value. A BiSrFeO3 multiferroic nanoparticles system exhibits both ferroelectric and ferromagnetic hysteresis loops. These results depict that the present samples can be regarded as a promising candidate for designing energy storage devices.

Ingeniously enhanced ferromagnetism in chemically-reduced 2D Ti3C2TX MXene

Chemical reduction is a facile and cost-effective technique for the modulation of the physical and chemical properties of nanomaterials. Herein, we demonstrate an enhancement of the magnetic behavior of Ti3C2Tx MXene after its chemical reduction via l-ascorbic acid treatment. Small ferromagnetic loops have been observed below 50 K for Ti3C2Tx prepared by hydrofluoric acid (HF) etching of Al layers from Ti3AlC2. Such a ferromagnetic ordering of spins was significantly enhanced via a chemical reduction of Ti3C2Tx with l-ascorbic acid. Ferromagnetic hysteresis loops were observed for reduced Ti3C2Tx (r-Ti3C2Tx) up to 150 K indicating a significant upshift of the paramagnetic to the ferromagnetic transition temperature, pushing towards room temperature. The enhancement of ferromagnetism and upshift of the ferromagnetic transition temperature could be attributed to the localized unpaired electron in Ti-3d orbital of the r-Ti3C2Tx crystal and increase in the number of unsaturated Ti atoms upon l-ascorbic acid treatment. Chemical reduction via l-ascorbic acid treatment shows a promising pathway towards the modulation and enhancement of magnetism in various MXene materials for the development of 2D metallic soft ferromagnets and spintronic devices.

Structural, Magnetic, and Dielectric Spectroscopy Investigations of Multiferroic Composite Based on Perovskite–Spinel Approach

Multiferroic composite materials with the nominal composition (La0.8Gd0.2FeO3)1−x(Mn0.5Cu0.5Fe2O4)x, x = 0.0≤x≤1 were prepared using the co-precipition method. XRD, FTIR and Raman were utilized to investigate the structure phase, microstructural characteristics, vibrational bands. The optical properties were analyzed; the VSM was used to investigate the magnetic properties of the composites. Broadband dielectric spectroscopy is employed to investigate the dielectric and electrical performance of the prepared multiferroic composites. Rietveld refinement of the XRD patterns confirmed the orthorhombic phase for lanthanum gadolinium iron oxide (La0.8Gd0.2FeO3) and cubic phase for manganese copper ferrite (Mn0.5Cu0.5Fe2O4). The crystallite size of LGFO phase pointed out that it increases with increasing the MCFO phase, while the microstrain found to decline. The FTIR results elucidated the tetrahedral and octahedral bands. The deduced optical properties revealed that the samples have optical energy gap in the range 4.18 −4.5 eV. The magnetic properties revealed that the composites exhibit typical ferromagnetic hysteresis loops, indicating the presence of ordered magnetic structure. The frequency dependence of permittivity ε′(f) and real part of complex conductivity, σ′(f) exhibits a development of a net of micro-capacitors like behavior that stores charge carriers.

Strain-induced modulation of magnetodielectric and magnetoelectric coupling in pzt/cfo thin films grown by rf-sputtering

The miniaturization of systems devices based on the magnetoelectric effect requires a better understanding of the factors that rule the coupling at the interface between different materials in magnetoelectric composites. In this context, this work presents the influence of stress generated at the interface PZT-CFO on multiferroic properties and the magnetodielectric coupling of the PbZr0,2Ti0,8O3/CoFe2O4 heterostructures fabricated by RF-Sputtering technique. It was found that tensile stress generated in the PZT/CFO interface modifies both XRD patterns and ferromagnetic hysteresis loop, inducing an additional contribution to the magnetic anisotropy compared with CFO and PZT layers. In addition, the dielectric properties of the PZT/CFO system are ruled by interfacial charges that accumulate in the PZT-CFO interface. On the other hand, changes in dielectric permittivity as a function of magnetic field (i.e., the magnetodielectric effects) result of the association between the ferroelectric domain movement modulated by stress on the PZT phase due to magnetostriction generated by the CFO phase and the magnetoelectric polarization contribution properly characterized by changes in the remnant polarization due to a magnetic field.

Strain-mediated ferromagnetism and low-field magnetic reversal in Co doped monolayer WS_2

Strain-mediated magnetism in 2D materials and dilute magnetic semiconductors hold multi-functional applications for future nano-electronics. Herein, First principles calculations are employed to study the influence of biaxial strain on the magnetic properties of Co-doped monolayer WS_2. The non-magnetic WS_2 shows ferromagnetic signature upon Co doping due to spin polarization, which is further improved at low compressive (-2 %) and tensile (+2 %) strains. From the PDOS and spin density analysis, the opposite magnetic ordering is found to be favourable under the application of compressive and tensile strains. The double exchange interaction and p-d hybridization mechanisms make Co-doped WS_2 a potential host for magnetism. More importantly, the competition between exchange and crystal field splittings, i.e. (Delta _{ex}>Delta _{cfs}), of the Co-atom play pivotal roles in deciding the values of the magnetic moments under applied strain. Micromagnetic simulation reveals, the ferromagnetic behavior calculated from DFT exhibits low-field magnetic reversal (190 Oe). Moreover, the spins of Co-doped WS_2 are slightly tilted from the easy axis orientations showing slanted ferromagnetic hysteresis loop. The ferromagnetic nature of Co-doped WS_2 suppresses beyond pm 2~% strain, which is reflected in terms of decrease in the coercivity in the micromagnetic simulation. The understanding of low-field magnetic reversal and spin orientations in Co-doped WS_2 may pave the way for next-generation spintronics and straintronics applications.

Various manifestations of weak magnetism and superconductivity in inclination interfaces of Bi, Sb and Bi1-xSbx

The magnetic properties of the nano-width bicrystal interfaces (CIs) of Bi, Sb and 3D topological insulator Bi1xSbx (0.06 ≤ x ≤ 0.2) are studied in a temperature range of 1.6–300 K. These materials do not show superconductivity under normal rhombohedral conditions and are anomalous diamagnetics. At the same time, two superconducting phases with Tc ≤ 21 K and magnetic hysteresis loops against a diamagnetic background typical for strong type II superconductors are identified in Bi interfaces. At the CIs of Bi1xSbx (0.06 ≤ x ≤ 0.2), as well as Sb, a superconducting transition and a ferromagnetic hysteresis loop or a dual loop (superimposed ferromagnetic and superconducting loops) against a paramagnetic background are observed; they indicate the simultaneous occurrence of superconductivity and weak ferromagnetism, which is specific to 3D topological insulators. The revealed coexistence of superconductivity and weak magnetism at these CIs is of significant interest for the fundamental physics and future applications in quantum computing and spintronic devices.