Doping dependent electronic and magnetic ordering in mixed-valent La1−xSrxMnO3 thin films

We have investigated the collective electronic and magnetic orderings of a series of La1−xSrxMnO3 thin films grown epitaxially strained to (001) oriented strontium titanate substrates as a function of doping, x, for 0 ≤ x ≤ 0.4. We find that the ground states of these crystalline thin films are, in general, consistent with that observed in bulk crystals and thin film samples synthesized under a multitude of techniques. Our systematic study, however, reveal subtle features in the temperature dependent electronic transport and magnetization measurements, which presumably arise due to Jahn-Teller type distortions in the lattice for particular doping levels. For the parent compound LaMnO3 (x = 0), we report evidence of a strain-induced ferromagnetic ordering in contrast to the antiferromagnetic ground state found in bulk crystals.

Magnetism-induced topological transition in EuAs3

The nature of the interaction between magnetism and topology in magnetic topological semimetals remains mysterious, but may be expected to lead to a variety of novel physics. We systematically studied the magnetic semimetal EuAs3, demonstrating a magnetism-induced topological transition from a topological nodal-line semimetal in the paramagnetic or the spin-polarized state to a topological massive Dirac metal in the antiferromagnetic ground state at low temperature. The topological nature in the antiferromagnetic state and the spin-polarized state has been verified by electrical transport measurements. An unsaturated and extremely large magnetoresistance of ~2 × 105% at 1.8 K and 28.3 T is observed. In the paramagnetic states, the topological nodal-line structure at the Y point is proven by angle-resolved photoemission spectroscopy. Moreover, a temperature-induced Lifshitz transition accompanied by the emergence of a new band below 3 K is revealed. These results indicate that magnetic EuAs3 provides a rich platform to explore exotic physics arising from the interaction of magnetism with topology.

First principles calculations of the structural, electronic, magnetic, and thermodynamic properties of the Nd2MgGe2 and Gd2MgGe2 intermetallic compounds

In recent years the intermetallic ternary RE2MgGe2 (RE = rare earth) compounds attract interest in a variety of technological areas. We therefore investigate in the present work the structural, electronic, magnetic, and thermodynamic properties of Nd2MgGe2 and Gd2MgGe2. Spin–orbit coupling is found to play an essential role in realizing the antiferromagnetic ground state observed in experiments. Both materials show metallicity and application of a Debye-Slater model demonstrates low thermal conductivity and little effects of the RE atom on the thermodynamic behavior.

Magnetic and electronic properties of CaFeO2Cl

CaFeO2Cl is a unique exception in the family of the iron oxyhalides. Its crystal structure is not related to the Ruddlesden-Popper phases as known for the other members, but contains layers of edge-sharing FeO2/2O3/3 pyramids without Fe–Cl contacts. The iron atoms form a distorted honeycomb substructure. Magnetization measurements on single crystals show an unexpected weak anisotropy and indicate antiferromagnetic ordering of the iron magnetic moments already at room temperature. 57Fe Mössbauer spectra confirm the trivalent oxidation state of iron and the presence of magnetic order. DFT calculations using the LDA + U approach support a Mott-insulating antiferromagnetic ground state and indicate a Néel-type ordered antiferromagnetic state in the honeycomb layer. The band gap from optical measurements is 1.3 eV and agrees with the red-brown colour as well as with the theoretical calculations.

Origin of ferromagnetism and the effect of doping on Fe3GeTe2

Fe3GeTe2 is found to have antiferromagnetic ground state spin order in its stoichiometric phase. It is a defect and doping that make this material ferromagnetic.

Electronic structure of the PrNiBi half-Heusler system based on the σGGA + U method

In this works, we study the electronic structure and magnetic properties of the Pr-Ni-Bi half-Heusler systems based on density functional theory. We use the σ GGA + U scheme to consider the effects of on-site electron-electron interactions. Results show that in contrast to the rough estimation of the total magnetic moment of the unit cell, based on the Slater-Pauling behavior in the half-Heusler systems, this system has an antiferromagnetic ground state because of the localized Pr-f electrons. By increasing the magnitude of the effective U parameter, band-inversion occurs in the band structure of this system, which shows the possibility of topological state occurrence.