We report the charge-order to ferromagnetic phase transition induced by pulsed high magnetic field and impurity doping effects in manganites La(0.4)Ca(0.6)(Mn(1-y)Cr(y))O3 (0 ≤ y ≤ 0.2). Significant charge-order suppression and ferromagnetic tendency upon the Cr(3+)-doping are evidenced, and three different ground states are identified, namely the charge-order state, the phase separated state, ...

An overview of some structural aspects of magnetic ordering is presented. Magnetic symmetry operations, point groups, and Bravais lattices will be utilized to describe the magnetic symmetry of various magnetic materials. Throughout the talk, the utilization of the theory of magnetic symmetry will be emphasized. The magnetic space groups of Fe, Co, Ni, α’-FeCo, CoPt, CrPt3, and Cu2MnAl will be e...

We address the issue of how triplet superconductivity emerges in an electronic system near a ferromagnetic quantum critical point (FQCP). Previous studies found that the superconducting transition is of second order, and T(c) is strongly reduced near the FQCP due to pair-breaking effects from thermal spin fluctuations. In contrast, we demonstrate that near the FQCP, the system avoids pair-break...

We study the antiferromagnetic RP2 model in four dimensions. We find a second order transition with two order parameters, one ferromagnetic and the other antiferromagnetic. The antiferromagnetic sector has mean-field critical exponents and a renormalized coupling which goes to zero in the continuum limit. The exponents of the ferromagnetic channel are not the mean-field ones, but the difference...

Densely packed atoms, molecules, or small particles can get trapped in a jammed state thereby avoiding crystallization. The resulting amorphous structures display complex, spatially heterogeneous, trapping potentials in stark contrast to the uniform case of a crystal. Here we study active and passive rotational motion in a jammed colloidal dispersion of particles consisting of an anti-ferromagn...

The discovery of the quantum Hall (QH) effect led to the realization of a topological electronic state with dissipationless currents circulating in one direction along the edge of a two-dimensional electron layer under a strong magnetic field. The quantum anomalous Hall (QAH) effect shares a similar physical phenomenon to that of the QH effect, whereas its physical origin relies on the intrinsi...

We study the influence of external pressure on the electronic and magnetic structure of EuMnO3 from first-principles calculations. We find a pressure-induced insulator-metal transition at which the magnetic order changes from A-type antiferromagnetic to ferromagnetic with a strong interplay with Jahn-Teller distortions. In addition, we find that the non-centrosymmetric E *-type antiferromagneti...

How can we understand a system that is too complicated to be simulated and in which some important quantities cannot be determined from observation? This is a question we were confronted with when we analyzed experimentally observed magnetic patterns in ultrathin ferromagnetic films. We have now, for this specific case, found a method that gives a good qualitative understanding of a surprising ...

Exact and/or rigorous results are reviewed for the Ising and XY /Villain spin glasses in finite dimensions, such as the exact energy, correlation identities and a functional relation between the distribution functions of ferromagnetic and spin glass order parameters. This last relation is useful to prove that the phase space is not complex on a line in the phase diagram. The spin wave theory ne...

Neutron scattering measurements show the ferromagnetic XY pyrochlore Yb2Ti2O7 to display strong quasi-two-dimensional (2D) spin correlations at low temperature, which give way to long range order (LRO) under the application of modest magnetic fields. Rods of scattering along 111 directions due to these 2D spin correlations imply a magnetic decomposition of the cubic pyrochlore system into decou...