Large Magnetic Entropy in Giant Magnetoresistive Amorphous Gadolinium Silicon
نویسندگان
چکیده
We report results of specific heat measurements from 5 to 70 K on thin films of the giant negative magnetoresistive spin glass a-GdxSi12x and its nonmagnetic analog a-YxSi12x . The specific heat of a-GdxSi12x samples is significantly greater than that of a-YxSi12x samples below 50 K. The resulting magnetic entropy of a-GdxSi12x exceeds the total calculated entropy available from Gd moments alone. We suggest that the additional entropy is provided by the interaction of barely localized electron spins with the Gd moments.
منابع مشابه
Gamma Irradiation Effect on Asymmetric Giant Magnetoimpedance of Co68.15Fe4.35Si12.5B15 Amorphous Alloy
The giant magneto impedance (GMI) effect is a large variation in the electrical impedance of a magnetic conductor when subjected to a static magnetic field. The sensitivity to the direction (AGMI) and magnitude of applied magnetic field and also linearity levels of this effect are three important parameters in magnetic sensors application. A suitable annealing procedure can be used to ac...
متن کاملModel for detection of immobilized superparamagnetic nanosphere assay labels using giant magnetoresistive sensors
Commercially available superparamagnetic nanospheres are commonly used in a wide range of biological applications, particularly in magnetically assisted separations. A new and potentially significant technology involves the use of these particles as labels in magnetoresistive assay applications. In these assays, magnetic bead labels are used like fluorescent labels except that the beads are exc...
متن کاملOverview of Amorphous and Nanocrystalline Magnetocaloric Materials Operating Near Room Temperature
The observation of a giant magnetocaloric effect in Gd5Ge1.9Si2Fe0.1 has stimulated the magnetocaloric research in the last two decades. However, the high price of Gd and its proclivity to corrosion of these compounds have prevented their commercial use. To reduce raw materials cost, transition metal-based alloys are investigated to replace rare earth-based materials. Environmental consideratio...
متن کاملSimulation of a Neutron Detector for Real Time Imaging Applications
Monte Carlo Method is used to simulate a double layer gadolinium-amorphous silicon thermal neutron detector. The detector fabricated in pixel array configuration has various applications including neutron imaging. According to the simulation results, a detector consisting of a gadolinium (Gd) film with thickness of 2-4 ~m, sandwiched properly with two layers of sufficiently thick (-30 ?µm) hydr...
متن کاملRecent Developments of Magnetoresistive Sensors for Industrial Applications
The research and development in the field of magnetoresistive sensors has played an important role in the last few decades. Here, the authors give an introduction to the fundamentals of the anisotropic magnetoresistive (AMR) and the giant magnetoresistive (GMR) effect as well as an overview of various types of sensors in industrial applications. In addition, the authors present their recent wor...
متن کامل