Showing papers on "Metamagnetism published in 1968"

Metamagnetism in TbAlO3

Abstract: Magnetization measurements have been carried out on single crystals of orthorhombic TbAlO3. The compound is antiferromagnetic below 3.8°K, where a sharp maximum in dχ/dT is observed. Single or double metamagnetic transitions, depending on the orientation of the applied field, are seen in the a‐b plane for fields above 7.5 kOe at 1.5°K. The data are interpreted with four sublattice model in which magnetic moments of 9 μB per ion are fixed by the crystal field at angles ±36° from the a axis in the a‐b plane.

Magnetic Ordering of Terbium in Some Perovskite Compounds

Abstract: Four perovskite compounds ATbO3 (A = Fe, Cr, Al, Co) are studied by means of neutron diffraction. Three Neel temperatures are distinguished. When A is magnetic and T < TN1, the A sublattice orders in a G mode; when T < TN2, the Tb sublattice orders and is coupled with A in the same irreducible representation of the space group Pbnm; finally when T < TN3, Tb orders in another mode which is decoupled from A, i.e., Tb orders in a different irreducible representation. The order in the latter case is the only one observed one if A is diamagnetic, and its origin is mainly dipolar. The Neel temperatures are given; the metamagnetism of Tb is studied for T < TN3.

Magnetic Anisotropies in Antiferromagnetic Rare Earth Antimonide Single Crystals

Abstract: The magnetic properties of the rare earth antimonides are anisotropic below ordering temperatures. In the compounds of Ce, Nd, Dy, and Ho the crystalline field confines the spin to the [100] axis. The observed uniaxial metamagnetism is explained in terms of the Ising model. The induced magnetic moments depend strongly on the direction of the applied field. This anisotropy is less pronounced in the cases of TbSb and ErSb, in good agreement with theoretical considerations. Metastable spin structures are observed in DySb, HoSb, and CeSb.

Magnetic Structure and Metamagnetism of HgCr2S4

Abstract: HgCr2S4 is a normal cubic spinel whose metamagnetic properties were first reported by Baltzer et al. Our neutron diffraction studies show that the magnetic structure at 4.2°K is a simple spiral, identical with that proposed by Plumier for ZnCr2Se4. The propagation vector τ is parallel to the symmetry axis of the spiral and directed along a particular cube edge in a given domain. The moment of Cr3+ is 2.73 μB, in agreement with the magnetization measurements, and the wavelength of the modulation is ∼42 A. The wavelength increases with temperature, reaching a value of ∼90 A at 30°K, and shows very little further variation up to the Neel point (∼60°K). Application of a magnetic field along a cube edge produces no magnetization in that direction, but rather a growth of domains for which τ ‖ H. This process is complete at ∼4 kOe and is followed by a rapid collapse of the spiral into the field direction which saturates at ∼10 kOe. The growth of favorably oriented domains decreases progressively as the direction...

Magnetic Properties of Some Rare Earth‐Aluminum Alloys

Abstract: The RAl alloys are orthorhombic; the structure can be described with a trigonal motif similar to a half‐cell of CsCl. The R3Al2 alloys are tetragonal. The magnetic properties of the RAl alloys, where R is any rare earth from Ce to Tm, and those of the R3Al2 alloys, with R passing from Gd to Tm, have been measured in fields up to 25 kOe or 60 kOe and at temperatures between 1.4° and 400°K. The RAl alloys, with R from Pr to Tb, order antiferromagnetically at temperature between 20°K (PrAl) and 72°K (TbAl); the magnetic configuration of TbAl has been studied by neutron diffraction; HoAl is ferromagnetic with a Curie point at 26°K; DyAl, ErAl and TmAl exhibit metamagnetism at 4.2°K. Gd3Al2 is ferromagnetic with a Curie point at 282°K, close to that of Gd; Dy3Al2 shows an antiferromagnetic transition near 20°K in zero field and metamagnetic behavior induced by a field below this temperature; its Curie point is 76°K. All compounds exhibit a Curie‐Weiss behavior above their transition points, with a paramagnetic moment close to that of the corresponding free tripositive rare earth ions.

The Magnetic and Crystallographic Properties of MnAs0.92P0.08

Abstract: The magnetic and crystallographic properties of polycrystalline MnAs0.92P0.08. were studied over a range of temperatures. A gradual distortion of the NiAs to the MnP structure coincides with an anomaly in the susceptibility curve, similar to that found with MnAs. It is suggested that the distortion of the NiAs structure results primarily from anion‐anion bonding. The susceptibility anomaly is attributed to an increase in the strength of the antiferromagnetic exchange coupling resulting from a decrease in Mn‐Mn separation during distortion. The appearance of metamagnetism at low temperatures is shown to be consistent with this view.

The magnetic and crystallographic properties of MnAs sub 0.92 P sub 0.08.

Abstract: Polycrystalline MnAsP crystallographic and magnetic properties over temperature range, discussing susceptibility anomaly, magnetic moment, distortion and metamagnetism