title: Enhancement of the coercivity in Co-Ni layered double hydroxides by increasing basal spacing.
abstract: The magnetic properties of layered double hydroxides (LDH) containing transition metal ions can still develop, compared with layered metal hydroxide salts which exhibit structure-dependent magnetism. In this article, we report the preparation of a hybrid magnet composed of Co-Ni LDH and n-alkylsulfonate anions (Co-Ni-CnSO3 LDH). As Co-Ni LDH is anion-exchangeable, we can systematically control the interlayer spacing by intercalating n-alkylsulfonates with different carbon numbers. The magnetic properties were examined with temperature- and field-dependent magnetization measurements. As a result, we have revealed that the coercive field depends on the basal spacing. It is suggested that increasing the basal spacing varies the competition between the in-plane superexchange interactions and long-range out-of-plane dipolar interactions. Moreover, a jump in the coercive field at around 20 Å of the basal spacing is assumed to be the modification of the magnetic ordering in Co-Ni-CnSO3 LDH.
authors.affiliation: Department of Chemistry, Keio University, 3-14-1 Hiyoshi, Yokohama 223-8522, Japan. einaga@chem.keio.ac.jp takyama@chem.keio.ac.jp.
authors.forename: Cuijuan
authors.initials: C
authors.lastname: Zhang
authors.forename: Tomoya
authors.initials: T
authors.lastname: Tsuboi
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Namba
authors.forename: Yasuaki
authors.initials: Y
authors.lastname: Einaga
authors.forename: Takashi
authors.initials: T
authors.lastname: Yamamoto