Magnetic Susceptibility Measurements of the Spin-½ Linear-Chainα-bis-(N-Methylsalicylaldiminato)-Copper (α-CuNSal)

The susceptibility of the spin-½ linear chain $\alpha$-CuNSal has been measured by the Faraday-balance technique from 2-300 K. The measurements over the entire range can be understood in terms of several approximations applicable to the high- or low-temperature regimes of the Heisenberg linear chain. From these models the nearest-neighbor-exchange strength has been obtained by two different techniques and its value determined to be $\frac{J}{k}=-3.2\mathrm{}\pm 0.2$ K. The excellent fit of the magnitude and temperature dependence of the data to these approximations over this wide temperature range confirms the one dimensionality of the system and yields an accurate measurement of the exchange constant.