Magnetic phenomena in Co-containing layered double hydroxides

Magnetic behavior of Co-II(n)Al-III layered double hydroxides (LDHs) (n = Co/Al = 2 and 3) intercalated with nitrate was studied as a function of temperature. Both LDH compounds are paramagnetic above about 8K. A rapid increase of their magnetic moments occurs below this temperature until the moments reach the maximum values at T-max of 4.0 K and 3.2 K for Co(2)Al-NO3 and Co(3)Al-NO3, respectively. Below T-max, the zero-field-cooled and the field-cooled static magnetization curves are strongly different. Along with this low-temperature phenomena, Co(2)Al-NO3 and Co(3)Al-NO3 demonstrate anomalous behavior of their temperature dependence magnetic susceptibility in a higher-temperature range: between 75 and 175 K, both the paramagnetic Curie temperature and the effective magnetic moment change in a non-monotonous way. Possible structural reasons of the observed magnetic behavior of the Co-II(n)Al-III LDHs are discussed. Published by AIP Publishing.