Concepts in Magnetism
Springer Proceedings in Physics 262 (2021) 39-62
Abstract:
I review some general concepts in magnetism including the nature of magnetic exchange (direct, indirect and superexchange), and how exchange interactions play out in multiple spin systems. The nature of atomic orbitals and the way in which they interact with the spin system is also considered. Several examples are also treated, including the Jahn–Teller interaction and its role in the properties in layered manganites.Inhomogeneous superconductivity in LuxZr1-xB12 dodecaborides with dynamic charge stripes
(2020)
Magnetic ground-state of the one-dimensional ferromagnetic chain compounds $M$(NCS)$_2$(thiourea)$_2$; $M$ = Ni, Co
(2020)
Magnetic order and disorder in a quasi-two-dimensional quantum Heisenberg antiferromagnet with randomized exchange
PHYSICAL REVIEW B 102:17 (2020) ARTN 174429
Abstract:
We present an investigation of the effect of randomizing exchange coupling strengths in the S=1/2 square lattice quasi-two-dimensional quantum Heisenberg antiferromagnet (QHAF) (QuinH)2Cu(ClxBr1-x)4·2H2O (QuinH = Quinolinium, C9H8N+), with 0≤x≤1. Pulsed-field magnetization measurements allow us to estimate an effective in-plane exchange strength J in a regime where exchange fosters short-range order, while the temperature TN at which long-range order (LRO) occurs is found using muon-spin relaxation, allowing us to construct a phase diagram for the series. We evaluate the effectiveness of disorder in suppressing TN and the ordered moment size, and we find an extended disordered phase in the region 0.4≲x≲0.8 where no magnetic order occurs. The observed critical substitution levels are accounted for by an energetics-based competition between different local magnetic orders. Furthermore, we demonstrate experimentally that the ground-state disorder is driven by quantum effects of the exchange randomness, which is a feature that has been predicted theoretically and has implications for other disordered quasi-two-dimensional QHAFs.Magnetically driven loss of centrosymmetry in metallic Pb2CoOsO6
PHYSICAL REVIEW B 102:10 (2020) ARTN 104410