Related papers: Low-Temperature Magnetization Relaxation in Magnet…
The swept-field experiments on magnetic molecular solids such as \Fe8 are studied using Monte Carlo simulations. A kinetic equation is developed to understand the phenomenon. It is found that the simulations provide a quantitatively…
We argue that to explain recent resonant tunneling experiments on crystals of Mn$_{12}$ and Fe$_8$, particularly in the low-T limit, one must invoke dynamic nuclear spin and dipolar interactions. We show the low-$T$, short-time relaxation…
We study the magnetic relaxation of a system of localized spins interacting through weak dipole interactions, at a temperature large with respect to the ordering temperature but low with respect to the crystal field level splitting. The…
The magnetization relaxation rate of small gamma-Fe2O3 particles dispersed in a silica matrix has been measured from 60 mK to 5 K. It shows a minimum around 150 mK, that can be discussed in terms of either thermal or quantum relaxation…
We model magnetization processes that take place through tunneling in crystals of single-molecule magnets, such as Mn_12 and Fe_8. These processes take place when a field H is applied after quenching to very low temperatures. Magnetic…
We show that correlations established before quenching to very low temperatures, later drive the magnetization process of systems of single molecule magnets, after a magnetic field is applied at t=0. We also show that in SC lattices, m…
Magnetization reversal in magnetic nanostructures is investigated numerically over time-scales ranging from fast switching processes on a picosecond scale to thermally activated reversal on a microsecond time-scale. A simulation of the…
We present magnetization studies in a series of phase separated La$_{0.5}$Ca$%_{0.5}$MnO$_{3}$ samples, with different low temperature fractions of the ferromagnetic (FM) and charge ordered-antiferromagnetic (CO-AFM) phases. A particular…
The time decay of the thermo-remanent magnetization (TRM) in Fe-Cr giant magnetoresistive (GMR) multilayers has been investigated. The magnetization in these multilayers relaxes as a function of time after being cooled in a small magnetic…
We study the slow phase of thermally activated magnetic relaxation in finite two-dimensional ensembles of dipolar interacting ferromagnetic nanoparticles whose easy axes of magnetization are perpendicular to the distribution plane. We…
We report Hall sensor measurements of the magnetic relaxation of Mn$_{12}$ acetate as a function of magnetic field applied along the easy axis of magnetization. Data taken at a series of closely-spaced temperatures between 0.24 K and 1.4 K…
Dynamic relaxation of the XY model quenched from a high temperature state to the critical temperature or below is investigated with Monte Carlo methods. When a non-zero initial magnetization is given, in the short-time regime of the dynamic…
Spin relaxation between the two lowest-lying spin-states has been studied in the S=4 single molecule magnet Ni$_4$ under steady state conditions of low amplitude and continuous microwave irradiation. The relaxation rate was determined as a…
Resonant microwave radiation applied to a single crystal of the molecular magnet Fe_8 induces dramatic changes in the sample's magnetization. Transitions between excited states are found even though at the nominal system temperature these…
We have performed realistic atomistic simulations at finite temperatures using Monte Carlo and atomistic spin dynamics simulations incorporating quantum (Bose-Einstein) statistics. The description is much improved at low temperatures…
We derive a simple system of equations to describe the magnetization relaxation of a molecular spin in weak interaction with a thermal bath for the whole temperature domain. Using this for the intermediate temperature domain where the…
The magnetic relaxation of ferromagnetic powders has been studied for many years, largely due to its importance to recording technologies. However, only recently have experiments been performed that resolve the magnetic state of individual…
We have studied the magnetic relaxation properties of the phase-separated manganite compound La0.250Pr0.375Ca0.375MnO3 . A series of polycrystalline samples was prepared with different sintering temperatures, resulting in a continuous…
We use Monte Carlo and molecular dynamics simulation to study a magnetic tip-sample interaction. Our interest is to understand the mechanism of heat dissipation when the forces involved in the system are magnetic in essence. We consider a…
We describe an experiment aimed at measuring the spin dynamics of the Fe8 single-molecule magnet in the presence of pulsed microwave radiation. In earlier work, heating was observed after a 0.2-ms pulse of intense radiation, indicating that…