title: Unusual magnetocaloric effect in R2Al (R = Dy, Ho, Er) compounds.
abstract: The magnetic properties of the orthorhombic intermetallic compounds R(2)Al (R = Dy, Ho, Er) are reported. Dy(2)Al undergoes a long-range canted antiferromagnetic-type ordering below T(1) = 105 K, and a further spin reorientation-type ordering below T(2) = 33 K. The low temperature magnetic state of the sample is found to be quite unusual, where a large hysteresis loop is observed in the magnetization curves (coercive field ∼ 33 kOe at 2 K). The isostructural compositions Ho(2)Al and Er(2)Al show multiple magnetic transitions: however, they do not show a large hysteresis loop at low temperature. Dy(2)Al is also associated with an interesting magnetocaloric effect, which is negative and moderate around T(1), but becomes large and positive below T(2). The observed behavior is related to the large magnetocrystalline anisotropy and narrow domain wall propagation coupled with a field-induced state at low temperature.
authors.affiliation: Department of Solid State Physics, Indian Association for the Cultivation of Science, 2A & B Raja S C Mullick Road, Kolkata 700 032, India.
authors.forename: A
authors.initials: A
authors.lastname: Bhattacharyya
authors.forename: S
authors.initials: S
authors.lastname: Giri
authors.forename: S
authors.initials: S
authors.lastname: Majumdar