Spin-phonon coupling in Gd(Co1/2Mn1/2)O3 perovskite

We have investigated the temperature-dependent Raman-active phonons and the magnetic properties of Gd(Co1/2Mn1/2)O3 perovskite ceramics in the temperature range from 40 K to 300 K. The samples crystallized in an orthorhombic distorted simple perovskite, whose symmetry belongs to the Pnma space group. The data reveals spin-phonon coupling near the ferromagnetic transition occurring at around 120 K. The correlation of the Raman and magnetization data suggests that the structural order influences the magnitude of the spin-phonon coupling.Comment: 3 Figures, suplementary materia

Role of topology in compensated magnetic systems

Topology plays a crucial and multifaceted role in solid state physics, leading to a remarkable array of newly investigated materials and phenomena. In this Perspective, we provide a brief summary of well-established model materials with a particular focus on compensated magnets and highlight key phenomena that emerge due to the influence of topology in these systems. The overview covers various magneto-transport phenomena, with a particular focus on the extensively investigated anomalous magneto-transport effects. Furthermore, we look into the significance of topology in understanding elementary magnetic excitations, namely magnons, where the role of topology gained considerable attention from both theoretical and experimental perspectives. Since electrons and magnons carry energy, we explore the implications of topology in combined heat and spin transport experiments in compensated magnetic systems. At the end of each section, we highlight intriguing unanswered questions in this research direction. To finally conclude, we offer our perspective on what could be the next advancements regarding the interaction between compensated magnetism and topology

Magneto-thermal transport indicating enhanced Nernst response in FeCo/IrMn exchange coupled stacks

We present an analysis of magneto-thermal transport data in IrMn/FeCo bilayers based on the Mott relation and report an enhancement of the Nernst response in the vicinity of the blocking temperature. We measure all four transport coefficients of the longitudinal resistivity, anomalous Hall resistivity, Seebeck effect, and anomalous Nernst effect, and we show a deviation arising around the blocking temperature between the measured Nernst coefficient and the one calculated using the Mott rule. We attribute this discrepancy to spin fluctuations at the antiferromagnet/ferromagnet interface near the blocking temperature. The latter is estimated by magnetometry and magneto-transport measurements

Anomalous Nernst effect in perpendicularly magnetised {\tau}-MnAl thin films

$\tau$-MnAl is interesting for spintronic applications as a ferromagnet with perpendicular magnetic anisotropy due to its high uniaxial magnetocrystalline anisotropy. Here we report on the anomalous Nernst effect of sputter deposited $\tau$-MnAl thin films. We demonstrate a robust anomalous Nernst effect at temperatures of 200 K and 300 K with a hysteresis similar to the anomalous Hall effect and the magnetisation of the material. The anomalous Nernst coefficient of (0.6$\pm$0.24) $\mu$V/K at 300 K is comparable to other perpendicular magnetic anisotropy thin films. Therefore $\tau$-MnAl is a promising candidate for spin-caloritronic research

Crystal growth, characterization and electronic band structure of TiSeS

Layered semimetallic van der Waals materials TiSe2 has attracted a lot of attention because of interplay of a charge density wave (CDW) state and superconductivity. Its sister compound TiS2, being isovalent to TiSe2 and having the same crystal structure, shows a semiconducting behavior. The natural rises what happens at the transition point in TiSe2-xSx, which is expected for x close to 1. Here we report the growth and characterization of TiSeS single crystals and the study of the electronic structure using density functional theory (DFT) and angle-resolved photoemission (ARPES). We show that TiSeS single crystals have the same morphology as TiSe2. Transport measurements reveal a metallic state, no evidence of CDW was found. DFT calculations suggest that the electronic band structure in TiSeS is similar to that of TiSe2, but the electron and hole pockets in TiSeS are much smaller. The ARPES results are in good agreement with the calculations.Comment: 22 pages, 9 figure

All Electrical Access to Topological Transport Features in Mn1.8_{1.8}PtSn Films

The presence of non-trivial magnetic topology can give rise to non-vanishing scalar spin chirality and consequently a topological Hall or Nernst effect. In turn, topological transport signals can serve as indicators for topological spin structures. This is particularly important in thin films or nanopatterned materials where the spin structure is not readily accessible. Conventionally, the topological response is determined by combining magnetotransport data with an independent magnetometry experiment. This approach is prone to introduce measurement artifacts. In this study, we report the observation of large topological Hall and Nernst effects in micropatterned thin films of Mn$_{1.8}$PtSn below the spin reorientation temperature $T_\mathrm{SR} \approx 190$K. The magnitude of the topological Hall effect $\rho_\mathrm{xy}^\mathrm{T} = 8$ n$\Omega$m is close to the value reported in bulk Mn$_2$PtSn, and the topological Nernst effect $S_\mathrm{xy}^\mathrm{T} = 115$ nV K$^{-1}$ measured in the same microstructure has a similar magnitude as reported for bulk MnGe ($S_\mathrm{xy}^\mathrm{T} \sim 150$ nV K$^{-1}$), the only other material where a topological Nernst was reported. We use our data as a model system to introduce a topological quantity, which allows to detect the presence of topological transport effects without the need for independent magnetometry data. Our approach thus enables the study of topological transport also in nano-patterned materials without detrimental magnetization related limitations.Comment: 8 pages, 3 figure