CABALLERO FLORES , Rafael

La tesis presenta un estudio del efecto magnetocalórico en materiales con transiciones de fase de segundo orden. Se centra esencialmente en la dependencia con el campo magnético aplicado de la variables termodinámicas relevantes del proceso, estudio de aleaciones basadas en hierro para minimizar los costos de los materiales refrigerantes, y...

In this paper, the influence of the Mn content on the magnetocaloric response of ribbon-shaped amorphous samples of Fe80−xMnxB20 x=10, 15, 18, 20, and 24 , has been studied. For this purpose, the temperature and field dependence of the magnetic entropy change SM have been obtained from magnetization curves. The partial substitution of Fe by...

The influence of the demagnetizing factor (N) on the magnetic entropy change (DSM) curves is studied for materials with a second order phase transition. For this purpose, a soft magnetic amorphous ribbon is measured for different orientations of the magnetic field with respect to the plane of the sample. For temperatures below the Curie...

In the current energy crisis scenario, the development of renewable energy forms such as energy storage systems among the supercapacitors is an urgent need as a tool for environmental protection against increasing pollution. In this work, we have designed a novel 3D nanostructured silver electrode through an antireplica/replica...

In the current energy crisis scenario, the development ofrenewable energy forms such as energy storage systems among the super-capacitors is an urgent need as a tool for environmental protection againstincreasing pollution. In this work, we have designed a novel 3D nanostructuredsilver electrode through an antireplica/replica template-assisted...

The series of glassy ribbons Gd 60 M 30 In 10 ( M ¼ Mn, Co, Ni, Cu) was synthesized by melt-spinning. The change of transition element M in these Gd-based metallic glasses was proven to induce huge variations of the Curie temperature T C , magnetic entropy change peak values D S m peak , and widths at half maximum values of the magnetic entropy...

The critical exponents of the alloy have been determined with the Kouvel–Fisher method to predict the field dependence of the magnetic entropy change DSM . The nonlinear fit of DSM ðHÞ to a power law provides a field exponent in perfect agreement with the predictions of the relevant scaling laws using the obtained critical exponent values. It...

The magnetocaloric response of Ni–Cu based multilayers has been studied with the aim of optimizing their magnetic field dependence. In contrast to the behavior of single phase materials, whose peak magnetic entropy change follows a power law with exponents close to 0.75, multilayering leads to exponents of ∼1 for an extended temperature span...

We have studied the magnetocaloric effect in a series of Fe88−2xCoxNixZr7B4Cu1Fe88−2xCoxNixZr7B4Cu1alloys. The partial substitution of Fe by Co and Ni leads to a monotonic increase in the Curie temperature(TC)(TC) of the alloys from 287 K for x=0x=0 to 626 K for x=11x=11. The maximum magnetic entropy change (ΔSpkM)(ΔSMpk) at an applied field of...

The refrigerant capacity (RC) of magnetocaloric materials can be enhanced using multiphase materials or composites, which expand the temperature range over which a significant magnetic entropy change can be obtained. Numerical simulations show that by controlling the parameters of the composite (the fraction of the different phases and their...

We have analyzed the overgrowth problem arising in decelerated growth processes of spherical crystals in the frame of classical nucleation and growth theory developed by Kolmogorov, Johnson and Mehl, and Avrami (KJMA). To do that, simulations of decelerated growth transformations with a constant nucleation rate have been performed, changing the...