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Exciting a ferromagnetic sample with an ultrashort laser pulse leads to a quenching of the magne- tization on a subpicosecond timescale. On the basis of the equilibration of intensive thermodynamic variables we establish a powerful model to describe the demagnetization dynamics. We demonstrate that the magnetization dynamics is mainly driven by the equilibration of chemical potentials. The minimum of magnetization is revealed as a transient electronic equilibrium state. Our method iden- tifies the slowing down of ultrafast magnetization dynamics by a critical region within a magnetic phase diagram.
High resolution ultrasonic velocity measurements have been used to determine the temperature -- magnetic-field phase diagram of the monoclinic multiferroic CuO. A new transition at TN3 = 230 K, corresponding to an intermediate state between the antif
Rare-earth-based permanent-magnet materials rich in iron have relatively low ferromagnetic ordering temperatures. This is believed to be due to the presence of antiferromagnetic exchange interactions, besides the ferromagnetic interactions responsibl
Three-dimensional (3D) antiferromagnets with random magnetic anisotropy (RMA) experimentally studied to date do not have random single-ion anisotropies, but rather have competing two-dimensional and three-dimensional exchange interactions which can o
Spin reorientation and magnetisation reversal are two important features of the rare-earth orthorhombic provskites ($RM$O$_{3}$s) that have attracted a lot of attention, though their exact microscopic origin has eluded researchers. Here, using densit
Erythrosiderites with the formula A2FeX5H2O, where A = Rb, K, and (NH4) and X = Cl and Br are intriguing systems that possess various magnetic and electric phases, as well as multiferroic phases in which magnetism and ferroelectricity are coupled. In