Open AccessThermodynamic properties of ferromagnetic films in variational cumulant expansi on
Author(s) -
Hong Chen,
Yan Yu-Li,
M. T. Hua
Publication year - 2003
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.52.2607
Subject(s) - magnetization , internal energy , cumulant , condensed matter physics , ferromagnetism , specific heat , atomic number , spontaneous magnetization , quantum , materials science , physics , thermodynamics , quantum mechanics , statistics , magnetic field , mathematics
The thermodynamical properties of quantum Heisenberg films are studied in variat ional cumulant expansion. The spontaneous magnetizationinternal energy and spe cific heat are calculated to the third order. For a thicknesses below a critical value, the magnetization decreases rapidly as the number of atomic layers is de creased. The internal energy increases with decreasing number of atomic layers at any given temperature, and the specific heat increases below the critical tem perature and decreases beyond the critical temperature with decreasing number o f atomic layers.