Variation of Exchange Integral<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>J</mml:mi></mml:math>with Lattice Spacing from Specific-Heat Measurements on Linear-Chain Antiferromagnets

Abstract

The specific heat of the copper tetrammine salt Cu${(\mathrm{N}{\mathrm{H}}_{3})}_{4}$S${\mathrm{O}}_{4}$ \ifmmode\cdot\else\textperiodcentered\fi{} N${\mathrm{H}}_{3}$ has been fitted to the Bonner-Fisher theory for linear magnetic chains of spin \textonehalf{} and with isotropic nearest-neighbor interaction, in the range 1-20 K. The exchange constant is $J=2.96\ifmmode\pm\else\textpm\fi{}0.02$ K. The results are compared with other similar linear-magnetic-chain copper salts to further confirm the simple power-law dependence of exchange interaction versus interionic spacing.