相关论文: Ultrafast ferromagnetic fluctuations preceding mag…
Tl$_{2}$Mn$_{2}$O$_{7}$ pyrochlores present colossal magnetoresistance (CMR) around the long range ferromagnetic ordering temperature (T$_{C}$). The character of this magnetic phase transition has been determined to be first order, by…
A variety of analytical techniques suggest that quantum fluctuations lead to a fundamental instability of the Fermi liquid that drives ferromagnetic transitions first order at low temperatures. We present both analytical and numerical…
We present a first-principles investigation of magnetic exchange interactions and critical behavior in (111)-oriented (LaMnO$_3$)$_{2n}$|(SrMnO$_3$)$_n$ superlattices for $n=2,4,6$. For all superlattices under investigation, we find robust…
We investigate the interplay of quantum fluctuations and magnetic anisotropies in metallic ferromagnets. Our central result is that fluctuations close to a quantum critical point can drive the moments to point along a magnetic hard axis. As…
We study, using simulations the dynamical properties of complex ferromagnetic granular materials. The system of grains is modeled by a disordered two-dimensional lattice in which the grains are embedded, while the magnitude and direction of…
We report $^{75}$As Nuclear Magnetic Resonance data in a single crystal of CaFe$_2$As$_2$. The Knight shift, electric field gradient, and spin-lattice relaxation rate are strongly temperature dependent in the paramagnetic state, and change…
The interplay between magnetic order, charge dynamics, and crystal field excitations underpins the emergent ground states of rare-earth intermetallics. Using time-domain terahertz spectroscopy, we probe this coupling in PrSi, a metallic…
Optically induced demagnetization of 3d metallic ferromagnets proceeds as fast as ~100 fs and is a crucial prerequisite for spintronic applications, such as ultrafast magnetization switching and spin transport. On the 100 fs time scale, the…
Itinerant metamagnetism transition is observed and studied in perovskite La1-xCaxMn0.90Cu0.10O3 system for x = 0.30. At a constant low temperature, 10 K < T < 150 K, there is a continuous second-order metamagnetism jump from a low magnetic…
We use neutron scattering to study the spin and lattice structures of single crystal and powder samples of Na$_{1-\delta}$FeAs ($T_c = 23$ K). On cooling from room temperature, the system goes through a series of phase transitions: first…
Phase transition is a fundamental phenomenon in condensed matter physics, in which states of matter transform to each other with various critical behaviors under different conditions. The magnetic martensitic transformation features…
Ferromagnetism is an iconic example of a first-order phase transition taking place in spatially extended systems and is characterized by hysteresis and the formation of domain walls. In this paper we demonstrate that an extended atomic…
Using a Dirac-Heisenberg Hamiltonian with biquadratic exchange interactions, we study the effect of iron disproportionation on the magnetic ordering, and describe the first-order magnetic transition occurring in the perovskite…
Recent results in electric-field control of magnetism have paved the way for the design of alternative magnetic and spintronic devices with enhanced functionalities and low power consumption. Among the diversity of reported magnetoelectric…
Magnetic cooling has the potential to replace conventional gas compression refrigeration. Materials such as La(Fe,Si)$_{13}$ exhibit a sizeable first-order magnetocaloric effect, and it is possible to tailor the phase transition towards…
We report a new manifestation of first-order magnetic transitions in two-dimensional electron systems. This phenomenon occurs in aluminum arsenide quantum wells with sufficiently low carrier densities and appears as a set of hysteretic…
The mixed state of type II superconductors has magnetic flux penetrating the sample in the form of vortices, with each vortex carrying an identical quantum of flux. These vortices generally form a triangular lattice under weak mutually…
First-order magnetostructural phase transitions underpin giant magnetocaloric effects, yet the microscopic role of lattice dynamics in these transitions remains controversial. Here we use first-principles spin-lattice dynamics simulations…
The discovery of superconductivity in LaFeAsO introduced the ferropnictides as a major new class of superconducting compounds with critical temperatures second only to cuprates. The presence of magnetic iron makes ferropnictides radically…
We investigate how emergent nematic order and nematic fluctuations affect several macroscopic properties of both the normal and superconducting states of the iron pnictides. Due to its magnetic origin, long-range nematic order enhances…