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Understanding the mechanisms for forming skyrmionic spin configurations at room temperature is essential for exploring the applicable spintronics devices based on topological spin textures. In this work, the anisotropic magnetic properties and critical behavior are investigated in noncollinear itinerant magnet PrMn2Ge2. The strongly anisotropic magnetic interactions and magnetic field and temperature induced antiferromagnetic to ferromagnetic transition are observed. The critical behavior of high temperature ferromagnetic transition at 331 K was analyzed, and the critical exponents β = 0.335, γ = 0.878, and δ = 3.617 are extracted by the modified Arrott plot method, which lie between the values of long-range mean-field and short-range three-dimensional theories, demonstrating that PrMn2Ge2 possesses multiple magnetic interactions. This is also confirmed by the moderated interaction function, which is decay as J(r) ∼ r − 4.69 . Therefore, the competition of multiple magnetic interactions in PrMn2Ge2 is analogous to what has been observed in GdRu2Si2 and could be the origin of skyrmionic bubbles observed at room temperature. [ABSTRACT FROM AUTHOR]

Spin-orbit coupled honeycomb magnets with the Kitaev interaction have received a lot of attention due to their potential of hosting exotic quantum states including quantum spin liquids. Thus far, the most studied Kitaev systems are 4d/5d-based honeycomb magnets. Recent theoretical studies predicted that 3d-based honeycomb magnets, including Na2Co2TeO6 (NCTO), could also be a potential Kitaev system. Here, we have used a combination of heat capacity, magnetization, electron spin resonance measurements alongside inelastic neutron scattering (INS) to study NCTO's quantum magnetism, and we have found a field-induced spin disordered state in an applied magnetic field range of 7.5 T < B (⊥ b-axis) < 10.5 T. The INS spectra were also simulated to tentatively extract the exchange interactions. As a 3d-magnet with a field-induced disordered state on an effective spin-1/2 honeycomb lattice, NCTO expands the Kitaev model to 3d compounds, promoting further interests on the spin-orbital effect in quantum magnets. The honeycomb lattice with a spin-orbit interaction can give rise to exotic quantum states. With the measurements of bulk properties and inelastic neutron scattering, Lin et al demonstrate the existence of a field induced spin-disordered state in Na2Co2TeO6 and extend the Kitaev model to 3d system. [ABSTRACT FROM AUTHOR]

We have presented the structural, surface morphology, magnetic and resistivity data for perovskite LaMnO3 epitaxial thin films which are fabricated on well-oriented (001) LaAlO3 substrates by pulsed laser deposition technique. X-ray diffraction 𝜃 – 2 𝜃 linear scans and reciprocal space mapping measurement confirm that the out-of-plane and in-plane epitaxial relationship are LMO(001)/LAO(001) and LMO(110)/LAO(110), respectively. Surface roughness determined by atomic force microscopy was no more than 0.3 nm. In the whole studied temperature range, all films only show a paramagnetic behavior instead of any magnetic phase transitions. Correspondingly, the electron transport behaviors always exhibit an insulting state as the temperature changes from high to low. However, we find that none of theoretical models can individually be used to understand their conductive mechanisms. Further studies indicated that charge carries of high and low temperature region obey adiabatic and nonadiabatic small polaronic hopping mechanisms, respectively. This finding offers new ways of exploiting the abnormal ferromagnetism in LaMnO3 multilayer thin films. [ABSTRACT FROM AUTHOR]

High-quality epitaxial LaCoO3 (LCO) thin films have been deposited on SrTiO3 (STO) substrates with pulsed laser deposition (PLD). We find that the LCO films undergo a typical ferromagnetic–paramagnetic (FM–PM) phase transition at ∼80 K. To understand the nature of magnetic phase transition, various methods, including the modified Arrott plot and critical isotherm analysis, were used to determine the critical exponents, which are β = 0.754(1) with a Curie temperature TC = 79.8(8) K and γ = 1.52(2) with TC = 79.9(2) K. The reliability of these critical exponents was confirmed using the Widom scaling relation and the scaling hypothesis. Further analysis revealed that the spin coupling within the LCO films exhibits two-dimensional (2D) long-range magnetic interaction and the magnetic exchange distance decays as J(r) ∼ r−(3.46). Our critical behavior analysis may shed new light on the further understanding of the origin of FM and the relatively fixed TC in LCO thin films. [ABSTRACT FROM AUTHOR]

While charge-ordering transition is well established in the oxygen-deficient layered cobaltite YBaCo2O5, there has been no evidence for the transition in the analogous compound GdBaCo2O5 either from neutron diffraction or from magnetic susceptibility experiments. In this paper, we present comparative studies on the electron spin resonance (ESR) of Gd3+ ions in Y1-xGdxBaCo2O5 (x = 0.01, 0.25, and 1) polycrystalline samples. Magnetic susceptibility was also performed for comparison with the ESR results. It was found that charge-ordering transition for Y0.75Gd0.25BaCo2O5 revealed by the susceptibility is also manifested in the characters of the ESR data. The similar temperature-evolution of the ESR parameters for GdBaCo2O5 provides a support for the existence of charge-ordering transition, although no characteristic of the transition is evidenced from susceptibility experiments, which can be understood as being hidden by dominant paramagnetism of Gd3+ ions in this compound. We have interpreted the temperature variation of ESR parameters in terms of electron localization associated with Co2+/Co3+ charge ordering. [ABSTRACT FROM AUTHOR]

Co3Sn2S2, a quasi-two-dimensional system with a kagome lattice, has been found to be a magnetic Weyl semimetal recently. In this work, the anisotropies of magnetization and transport properties of Co3Sn2S2 were investigated. The high field measurements reveal a giant magnetocrystalline anisotropy with an out-of-plane saturation field of 0.9 kOe and an in-plane saturation field of 230 kOe at 2 K, showing a magnetocrystalline anisotropy coefficient Ku up to 8.3 × 105 J m−3, which indicates that it is extremely difficult to align the small moment of 0.29 μB/Co on the kagome lattice from the c axis to the ab plane. The out-of-plane angular dependence of Hall conductivity further reveals strong anisotropies in the Berry curvature and ferromagnetism, and the vector directions of both are always parallel with each other. For the in-plane situation, the longitudinal and transverse measurements for both I // a and I ⊥ a cases show that the transport on the kagome lattice is isotropic. These results provide the essential understanding of the magnetization and transport behaviors for the magnetic Weyl semimetal, Co3Sn2S2. [ABSTRACT FROM AUTHOR]

The magnetic and electronic transport properties of the lightly doped SrRu1-x Fex O3 (x ≤ 0.15) have been studied. All the samples show a paramagnetic-ferromagnetic phase transition and hysteresis effect. With the increase of Fe, the temperature of magnetic phase transition decreases but coercive field increases indicting the existence of antiferromagnetic interaction and magnetic-crystalline anisotropy. In low temperature, all the doping samples exhibit an insulating behavior while metal feature appears only at x ≤ 0.10 samples. The induced disorder suppresses the itinerant property of Ru 4d electron due to Fe random occupation. As a result, the ferromagnetism is weakened and metal-insulator transition is suppressed. [ABSTRACT FROM AUTHOR]