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The quasi-two-dimensional ferromagnet Cr5Te8 is a promising material for spintronic devices due to its near-room-temperature Curie temperature ( T C ), strong magnetic anisotropy, and easily controllable properties. In this study, the anisotropic magnetization of trigonal (T-) Cr5Te8 single crystals is investigated. Our magnetization study reveals that a ferromagnetic transition occurs when the magnetic field is aligned parallel to the c-axis (H / / c), while an antiferromagnetic transition appears for H / / a b , with a strong perpendicular anisotropy in the ground state. However, electron spin resonance (ESR) spectroscopy indicates that the direction of the easy-axis changes from the c-axis to the ab-plane at T V ∼ 190 K as the temperature increases. Furthermore, angle-dependent ESR spectra demonstrate a characteristic of two-dimensional magnetism in the bulk Cr5Te8 single crystal. It is suggested that the temperature-dependent variation in anisotropy is caused by changes in lattice structure through the tuning of the dominant direct-exchange between the intralayers and the super-exchange within the interlayers. The temperature- and field-dependent microwave responses of T-Cr5Te8 are advantageous for the application of this material as a microwave-based spintronic device. [ABSTRACT FROM AUTHOR]

Double perovskites such as Sr2CrReO6 attract great scientific attention owing to their high Curie temperatures (TC ≥ 550 K) as well as large magnetoresistances. However, both the specific physical mechanism of high TC and magnetic ground state in Sr2CrReO6 remain ill‐defined. In order to clarify and understand these issues, we studied its critical phase transition characteristics using critical behavior analysis. We found that the obtained critical exponents (β = 1.115 and γ = 2.224) are quite different from any traditional universality class. The abnormal critical behavior implies that at the quantum critical point, Sr2CrReO6 exists a strong competition among several magnetic interactions. By analyzing their effective critical exponents, we show that the double perovskite Sr2CrReO6 is really an ordered and homogeneous ferromagnet. With the help of Takahashi's theory, the nature of ferromagnetism in Sr2CrReO6 is confirmed to be localized instead of itinerant. The results of this research will provide new insights into the origins of high TC as well as the magnetic ground state in this double perovskite. [ABSTRACT FROM AUTHOR]

The 2D chromium telluride family (CrxTey) is an outstanding candidate for creating high‐density and dissipationless nanodevices because of its high Curie temperature, chiral spin patterns, and large saturation magnetic moment. However, the precise magnetic exchange mechanism and crucial phase transitional property of CrxTey must be fully analyzed. Herein, a large‐area CrTe (x:y = 1:1) single‐crystalline films deposited on an Al2O3 substrate. Based on the analysis of critical isothermal magnetization around the Curie temperature TC = 201 K and the modified Arrott plot, the precise critical exponents β = 0.386(3) and γ = 1.391(2) are obtained. Both their reliability and accuracy are also verified by Kouvel–Fisher theory, Widom scaling law, and scaling equation. Moreover, using the renormalization group theory, it is confirmed that CrTe belongs to a quasi‐2D Heisenberg‐like behavior with long‐range interactions. Finally, the density functional theory calculations indicate that, near the Fermi level, the CrTe band structure is mainly composed of Cr atom. The spin‐polarized density of states shows that the total magnetic moments are determined mainly by the polarized spin‐up t2g electron of Cr atom. This work is an important asset for a series of CrxTey materials in future spintronic applications. [ABSTRACT FROM AUTHOR]

Chromium-intercalated hexagonal Cr1∕3TaS2 possesses exotic properties, such as high-temperature magnetic soliton, crossover of critical behavior, and nontrivial magnetism. In this study, we employ the electron spin resonance (ESR) technique to modulate and study the chiral magnetic soliton lattice (CSL) in Cr1∕3TaS2 using microwave at X-band. The experimental results show that Cr1∕3TaS2 has a particularly strong microwave response when H ⊥ c but very weak feedback when H / / c , revealing an anisotropic microwave response. When H ⊥ c , the resonance peak at lower fields results from the surface barrier induced by the competition between Dzyaloshinsky–Moriya interaction, Zeeman energy, and exchange energy. The dominant resonance is caused by the ferromagnetic mode with the twisted region as the boundary condition, which transforms into a paramagnetic resonance above the phase transition temperature (TC). Furthermore, an unusual temperature dependence of ESR spectra is revealed. The crystalline electric field (CEF) excitation owing to large strong spin–orbit coupling results in the widening of the ESR linewidth above TC. Furthermore, an abrupt shift in the resonance field H r 2 and ESR linewidth Δ H P P 2 is observed around TC, which is attributed to a sudden change in spin-exchange interactions and magnetic anisotropy around TC, as Cr1∕3TaS2 was previously observed for spin interaction transition from strong anisotropic 3D-Ising type to isotropic 3D-Heisenberg magnetic interaction below TC. This work demonstrates that the ESR can detect the CSL state and investigate materials with nontrivial magnetism. [ABSTRACT FROM AUTHOR]

The interaction between complex magnetic structures and non-trivial band structures in ternary rare-earth GdCr6Ge6 induces exotic and abundant electro-magnetic phenomena. In this work, we perform a systematical investigation on critical behaviors and magnetic properties of the single-crystal GdCr6Ge6. The temperature, field, and angle dependence of magnetization unveils strong magnetic anisotropy along the c-axis and isotropic characteristic in the ab-plane. Critical exponents β = 0.252(1), γ = 0.905(9), δ = 4.606(3) for H//ab, and β = 0.281(3), γ = 0.991(8), δ = 4.541(5) for H//c are obtained by the modified Arrott plot method (MAP) and critical isotherm (CI) analysis. The determined exponents for both directions are consistent with the theoretical prediction of a tricritical mean-field model. Based on detailed magnetization measurements and universality scaling, comprehensive magnetic phase diagrams of GdCr6Ge6 for H//ab and H//c are constructed, which reveal that the external field induces a ferromagnetic (FM) transition for H//ab while a ferrimagnetic (FIM) one for H//c. Two tricritical points are determined for H//ab (11.2 K, 266.3 Oe) and H//c (11.3 K, 3.3 kOe) on the phase diagrams, respectively. The field-induced anisotropic magnetic configurations and multiple phases are clarified, where the moments of Gd and Cr form FM coupling for H//ab while FIM one for H//c via the interaction between Gd and Cr sublattices. [ABSTRACT FROM AUTHOR]

The La0.88Sr0.12MnO3 nanocrystalline is synthesized by sol-gel chemical method, shows a typical paramagnetic-ferromagnetic phase transition at 280 K. A thorough study on critical behavior analysis of magnetization isotherms is performed by various techniques such as modified Arrott plot, Kouvel-Fisher method, and critical isotherm analysis. Based on these methods, the accurate critical exponents (β = 0.5936(2) and γ = 1.0928(6)) are determined. Both critical exponents (β and γ) have been confirmed to fulfill the Widom scaling relation δ = 1+ γ β . Moreover, these exponents also obey the single scaling equation of H M δ = h ( ε H 1 / β ) . The obtained critical exponents are closer to the theoretical prediction of mean-field model but shows a slight deviation from theoretical values. We proposed that this deviation is due to the inherent disorder effect as the dimension of La0.88Sr0.12MnO3 particles reduced to nanoscale. Highlight: La0.88Sr0.12MnO3 nanocrystalline is prepared by the sol-gel method. The critical properties associated with the ferromagnetic transition are investigated by various techniques. The critical exponents show a slight deviation from theoretical values due to the inherent disorder effect when the La0.88Sr0.12MnO3 particles reduced to nanoscale. [ABSTRACT FROM AUTHOR]