2004/04/30 by S. S. Sosin, L. A. Prozorova, Alex I. Smirnov +6
Materials Science · Physics and Astronomy · #Advanced Condensed Matter Physics #Magnetic and transport properties of perovskites and related materials #Multiferroics and related materials #cond-mat.stat-mech #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.71.094413
published as Phys. Rev. B 71, 094413 (2005) · 6 pages, 4 figures, accepted version
arxiv created 2004/12/17 · openalex publication_date 2005/03/11 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
An adiabatic demagnetization process is studied in Gd2Ti2O7, a geometrically frustrated antiferromagnet on a pyrochlore lattice. In contrast to conventional paramagnetic salts, this compound can exhibit a temperature decrease by a factor of 10 in the temperature range below the Curie-Weiss constant. The most efficient cooling is observed in the field interval between 120 and 60\phantom\rule0.3em0exkOe corresponding to a crossover between saturated and spin-liquid phases. This phenomenon indicates that a considerable part of the magnetic entropy survives in the strongly correlated state. According to the theoretical model, this entropy is associated with a macroscopic number of local modes remaining gapless until the saturation field. Monte Carlo simulations on a classical spin model demonstrate good agreement with the experiment. The cooling power of the process is experimentally estimated with a view to possible technical applications. The results for Gd2Ti2O7 are compared to those for Gd3Ga5O12, a well-known material for low temperature magnetic refrigeration.