相关论文: Manifestation of finite temperature size effects i…
In the framework of the diagrammatic method with self-consistent field, the maximum on the temperature dependence of the susceptibility of a weakly doped narrow-band Hubbard magnet below the Curie temperature $T_{\rm C}$ is predicted. By…
Seeking to unravel the enigmatic Verwey transition and its interplay with magnetism, we have conducted comprehensive measurements on the temperature-dependent electrical resistivity and magnetic moment of stoichiometric and doped-magnetite…
We provide experimental evidence that the upper limit of ~110 K commonly observed for the Curie temperature T_C of Ga(1-x)Mn(x)As is caused by the Fermi-level-induced hole saturation. Ion channeling, electrical and magnetization…
$^{195}$Pt-NMR measurements of Pt nanoparticles with a mean diameter of 4.0 nm were performed in a high magnetic field of approximately $\mu_0 H = 23.3$ T to investigate the low-temperature electronic state of the nanoparticles. The…
We report on the magnetic properties of monovacancy defects in neutron-irradiated graphite, probed by $^{13}$C nuclear magnetic resonance spectroscopy. The bulk paramagnetism of the defect moments is revealed by the temperature dependence…
In the immediate vicinity of the critical temperature (T$_c$) of a phase transition, there are fluctuations of the order parameter, which reside beyond the mean-field approximation. Such critical fluctuations usually occur in a very narrow…
The role of particle size distribution inherently present in magnetic nanoparticles (NPs) is examined in considerable detail in relation to the measured magnetic properties of oleic acid-coated maghemite ({\gamma}-Fe$_2$O$_3$) NPs.…
The Curie temperature TC is investigated as a function of the hole concentration p in thin films of ferromagnetic semiconductor (Ga,Mn)As. The magnetic properties are probed by transport measurements and p is varied by the application of an…
Magnets with controllable magnetization and high critical temperature are essential for practical spintronics devices, among which the two-dimensional 1T-CrTe2 stands out because of its high experimental critical temperature up to about…
Although ferromagnetism is in general a long-range collective phenomenon, it is possible to induce local spatial variations of magnetic properties in ferromagnetic materials. For example, systematic variation of the exchange coupling…
In this article, the Curie-Weiss type behavior and the appearance of an "interaction" or "ordering" temperature for a collection of magnetic nanoparticles is explored theoretically. We show that some systems where an interaction temperature…
Quantum size effect-induced heat capacity of metal nanoparticles at low temperatures was predicted 79 years ago to be exponential. This, however, has not been reported until date. In defiance, we demonstrate here observation of…
Magnetic properties of polycrystalline samples of RuSr$_2$(Gd$_{1.5}$Ce$_{0.5}$)Cu$_{2}$O$_{10-\delta}$, as-prepared (by solid-state reaction) and annealed (12 hours at 845$^{\circ}$C) in pure oxygen at different pressure (30, 62 and 78…
The DC transport properties of and the radio-frequency (RF) wave absorption (at 2.525 MHz) in a sample of La$_{0.67}$Sr$_{0.33}$MnO$_{3}$ prepared by floating-zone method are measured. The Curie temperature, $T_{c}$, of the sample is about…
Bismuth-metal graphite (MG) has a unique layered structure where Bi nanoparticles are encapsulated between adjacent sheets of nanographites. The superconductivity below $T_{c}$ (= 2.48 K) is due to Bi nanoparticles. The Curie-like…
Recent realizations of intrinsic, long-range magnetic orders in two-dimensional (2D) van der Waals materials have ignited tremendous research interests. In this work, we employ the XXZ Heisenberg model and Monte Carlo simulations to study a…
The results of magnetoresistance ($\Delta \rho /\rho$)measurements in GdNi, in the temperature range 4.2 to 300 K are reported. The sign of $\Delta \rho /\rho $ above the Curie temperature (Tc= 70 K) is negative and its magnitude in a…
We have investigated the magnetic properties of carbon powders which consist of nanodisks, nanocones, and a small fraction of carbon-black particles. Magnetization measurements were carried out using a superconducting quantum interference…
Molecular beam epitaxy has been employed to obtain Ga1-xMnxN films with x up to 10% and Curie temperatures T_C up to 13 K. The magnitudes of T_C and their dependence on x, T_C(x) ~ x^m, where m = 2.2 +/- 0.2 are quantitatively described by…
Below the Curie temperature T_c of a Heusler-alloy film, consisting of densely packed, but exchange-decoupled nanograins, the spontaneous magnetization M_s(T) and static in-plane susceptibility \chi_{||}(T) increase very slowly signalizing…