Magneto-Optical Properties of Rare-Earth Terbium Ferrite-Garnet in the Near the Temperature of the Orientation Phase Transition

A model of the rearrangement of the domain structure of the Tb0.2Y2.8Fe5O12 garnet ferrite in the temperature region of the spontaneous reorientation of the easy magnetization axis is proposed, which makes it possible to consistently describe (at a qualitative level) the entire set of experimental results obtained. The latter makes it possible to make a choice in favor of the fluctuation mechanism of nucleation of domains of a new magnetic phase in the process of reorientation of the direction of the easy magnetization axis.

Cubic 3D Chern photonic insulators with orientable large Chern vectors

Time Reversal Symmetry (TRS) broken topological phases provide gapless surface states protected by topology, regardless of additional internal symmetries, spin or valley degrees of freedom. Despite the numerous demonstrations of 2D topological phases, few examples of 3D topological systems with TRS breaking exist. In this article, we devise a general strategy to design 3D Chern insulating (3D CI) cubic photonic crystals in a weakly TRS broken environment with orientable and arbitrarily large Chern vectors. The designs display topologically protected chiral and unidirectional surface states with disjoint equifrequency loops. The resulting crystals present the following characteristics: First, by increasing the Chern number, multiple surface states channels can be supported. Second, the Chern vector can be oriented along any direction simply changing the magnetization axis, opening up larger 3D CI/3D CI interfacing possibilities as compared to 2D. Third, by lowering the TRS breaking requirements, the system is ideal for realistic photonic applications where the magnetic response is weak.

Cubic 3D Chern photonic insulators with orientable large Chern vectors

Time Reversal Symmetry (TRS) broken topological phases provide gapless surface states protected by topology, regardless of additional internal symmetries, spin or valley degrees of freedom. Despite the numerous demonstrations of 2D topological phases, few examples of 3D topological systems with TRS breaking exist. In this article, we devise a general strategy to design 3D Chern insulating (3D CI) cubic photonic crystals in a weakly TRS broken environment with orientable and arbitrarily large Chern vectors. The designs display topologically protected chiral and unidirectional surface states with disjoint equifrequency loops. The resulting crystals present the following novel characteristics: First, by increasing the Chern number, multiple surface states channels can be supported. Second, the Chern vector can be oriented along any direction simply changing the magnetization axis, opening up larger 3D CI/3D CI interfacing possibilities as compared to 2D. Third, by lowering the TRS breaking requirements, the system is ideal for realistic photonic applications where the magnetic response is weak.

Manipulation of the Magnetic Properties of Janus WSSe Monolayer by the Adsorption of Transition Metal Atoms

Two-dimensional Janus materials have great potential for the applications in spintronic devices due to their particular structures and novel characteristics. However, they are usually non-magnetic in nature. Here, different transition metals (TMs: Co, Fe, Mn, Cr, and V) adsorbed WSSe frameworks are constructed, and their structures and magnetic properties are comprehensively investigated by first-principles calculations. The results show that the top of W atom is the most stable absorption site for all the TM atoms, and all the systems exhibit magnetism. Moreover, their magnetic properties significantly depend on the adsorbed elements and the adsorbent chalcogens. A maximal total magnetic moment of 6 μB is obtained in the Cr-adsorbed system. The induced magnetism from S-surface-adsorption is always stronger than that for the Se-surface-adsorption due to its larger electrostatic potential. Interestingly, the easy magnetization axis in the Fe-adsorbed system switches from the in-plane to the out-of-plane when the adsorption surface changes from Se to S surface. The mechanism is analyzed in detail by Fe-3d orbital-decomposed density of states. This work provides a guidance for the modification of magnetism in low-dimensional systems.

Manipulation of The Magnetic Properties of Janus WSSe Monolayer By The Adsorption of Transition Metal Atoms

Two-dimensional Janus materials have great potential for the applications in spintronic devices due to their particular structures and novel characteristics. However, they are usually non-magnetic in nature. Here, different transition metals (TMs: Co, Fe, Mn, Cr, and V) adsorbed WSSe frameworks are constructed, and their structures and magnetic properties are comprehensively investigated by first-principles calculations. The results show that the top of W atom is the most stable absorption site for all the TM atoms, and all the systems exhibit magnetism. Moreover, their magnetic properties significantly depend on the adsorbed elements and the adsorbent chalcogens. A maximal total magnetic moment of 6 μB is obtained in the Cr-adsorbed system. The induced magnetism from S-surface-adsorption is always stronger than that for the Se-surface-adsorption due to its larger electrostatic potential. Interestingly, the easy magnetization axis in the Fe-adsorbed system switches from the in-plane to the out-of-plane when the adsorption surface changes from Se to S surface. The mechanism is analyzed in detail by Fe-3d orbital-decomposed density of states. This work provides a guidance for the modification of magnetism in low-dimensional systems.

Magnetic Anisotropy Induced by Orbital Occupation States in La0.67Sr0.33MnO3 Film

Interface engineering is an effective and feasible method to regulate the magnetic anisotropy of films by altering interfacial states between different films. Using the technique of pulsed laser deposition, we prepared La0.67Sr0.33MnO3 (LSMO) and La0.67Sr0.33MnO3/SrCoO2.5 (LSMO/SCO) films on the (110)-oriented La0.3Sr0.7Al0.65Ta0.35O3 substrates. By covering the SCO film above the LSMO film, we transformed the easy magnetization axis of LSMO from the [001] axis to the [1\(\stackrel{\text{-}}{\text{1}}\)0] axis in the film plane. Based on statistical analyses, we found that the corresponding Mn-Mn ionic distances are different in the two types of LSMO films, causing different distortions of Mn-O octahedron in the LSMO film. In addition, it also induces diverse electronic occupation states in Mn3+ ions. The eg electron of Mn3+ occupies 3z2-r2 and x2-y2 orbitals in the LSMO and LSMO/SCO, respectively. We conclude that the electronic spin reorientation leads to the transformation of the easy magnetization axis in the LSMO films.

Comparison of two superconducting phases induced by a magnetic field in UTe2

Superconductivity induced by a magnetic field near metamagnetism is a striking manifestation of magnetically-mediated superconducting pairing. After being observed in itinerant ferromagnets, this phenomenon was recently reported in the orthorhombic paramagnet UTe2. Here we explore the phase diagram of UTe2 under two magnetic-field directions: the hard magnetization axis b, and a direction titled by ≃25-30° from b in the (b,c) plane. Zero-resistivity measurements confirm that superconductivity is established beyond the metamagnetic field Hm in the tilted-field direction. While superconductivity is locked exactly at fields either smaller (for H | | b), or larger (for H tilted by ≃27° from b to c), than Hm, the variations of the Fermi-liquid coefficient in the electrical resistivity and of the residual resistivity are similar for the two field directions. The resemblance of the normal states for the two field directions puts constraints for theoretical models of superconductivity and implies that some subtle ingredients must be in play.

Радиальные домены в микропроводах DyPr-FeCo-B

In DyPr-FeCo-B microwires with an easy magnetization axis directed along the microwire axis, domains with radial magnetization were found by the method of magneto-optical indicator films (MOIF). The width of the radial domains decreases with increasing field up to 30 mT, and increases with increasing diameter of the microwire in the range 60 - 105 μm. In wires of smaller diameter, the critical field for the appearance of radial domains is smaller. The influence of periodic scratches on the distribution of magnetization perpendicular to the microwire is found.