Spin-glass-like complex susceptibility of frozen magnetic fluids

Magnetic susceptibility and order parameter of the spin-glass-like phase of the double-exchange model.

The magnetic susceptibility and Edwards-Anderson order parameter q of the spin-glass-like (SGL) phase of the double-exchange model are evaluated in the weak-coupling or RKKY limit. Dynamical mean-field theory is used to show that q = M(T/T(SGL))2, where M is the classical Brillouin function and T(SGL) is the SGL transition temperature. The correlation length of the SGL phase is determined by a ...

Second-order-like cluster-monomer transition within magnetic fluids and its impact upon the magnetic susceptibility

The low-field (below 5 Oe) ac and dc magnetic response of a magnetic fluid [MF] sample in the range of 305 to 360 K and 410 to 455 K was experimentally and theoretically investigated. We found a systematic deviation of Curie's law, which predicts a linear temperature dependence of inverse initial susceptibility in the range of our investigation. This finding, as we hypothesized, is due to the o...

MAGNETIC FIELD DEPENDENCE OF THE SUSCEPTIBILITY AND SPECIFIC HEAT IN A (La, Gd) Al2 SPIN GLASS

The linear magnetic specific heat, C^ = yT, of (Lao.92do.b8)2 is reduced in a magnetic field H. For H £ 1 tesla, y(H) is explained within the RKKY model. The steep decrease of y already in small fields (H < 0.1 tesla) is compared to the strong depression of the susceptibility and interpreted as being due to the blocking of superparamagnetic clouds. The predominant features of spin glasses, the ...

Spin-glass-like ordering of the magnetic moments of interacting nanosized maghemite particles.

Anomaly of Ac Resistance in Magnetic Nanoparticle Alloys at Spin-glass-like Transition

A combined study of magnetic susceptibility and AC resistance was performed on melt-spun Cu-Co granular magnetic ribbons. The AC resistance as a function of temperature has a sharp maximum. We associate it with a diverging correlation length at the temperature of collective freezing of magnetic moments via increasing magnetic losses in the induced non-uniform field. Application of this model to...