Magnetic properties and thermal treatments in pseudobinary TbPt_1 xCu_xalloys

Abstract

The structural and magnetic properties of the TbPt1−xCux orthorhombic compounds are studied in two series of samples: prepared ‘as quenched’ and after an annealing treatment. An extended analysis of the influence of the annealing in the microstructure of the samples was performed by x-ray, neutron diffraction and scanning electron microscopy. This analysis allows us to understand the modifications in the magnetic properties of both series, as a consequence of the sample homogenization process. Changes from ferromagnetism to antiferromagnetism with increasing Cu concentration are found in both series despite the ionic distance invariance. x = 0.3 is the composition limit between both behaviours. This study strongly supports the importance of the conduction band state rather than ionic distances in the magnetic behaviour of these rare earth–d compounds.

Phase transition of intermetallic TbPt at high temperature and high pressure

“…Pressure-volume data are fitted to a third-order Birch-Murnaghan equation of state (BM3-EoS) using errorweighted least squares with EoSFit7c software [17]. The resulting BM3-EoS parameters are as follows: V 0 = 175.5(2) Å 3 , K T0 = 110(5) GPa and K T0 = 3.8 (7), which is comparable to volume at ambient conditions (V 0 = 174.98 Å 3 ) measured by Señas et al [8] using an XRD method. Then we performed BM2-EoS fit (K 0 = 4 implied) to the current dataset, yielding the results: V 0 = 175.5(2) Å 3 and K T0 = 108(2) GPa.…”

“…Some previous research has performed a systematic study on the magnetic properties of TbPt x Cu 1−x series using XRD, neuron diffraction and scanning electron microscopy techniques [8,9,11]. The transition from ferromagnetism (FM) to antiferromagnetism (AFM) with increasing Cu concentration has been studied without the variance of ionic distance.…”

“…and the crystal structure can be described as being composed of platinum trigonal prisms (figure 1). The Pnma structure TbPt is stable at ambient temperature and pressures [7][8][9]. To the best of our knowledge, there has been no previous research that presented the results of structural and magnetic properties of TbPt at room-temperature high-pressure conditions.…”

“…To the best of our knowledge, there has been no previous research that presented the results of structural and magnetic properties of TbPt at room-temperature high-pressure conditions. Most of the previous studies have focused on the magnetic properties and magnetic structure of TbPt at very low temper ature (~1.5 to 67 K) and low pressure (up to 6.5 GPa) [8,10]. Moreover, the structure and elastic behaviors of TbPt at high pressure and temperature conditions are still unknown.…”

TbPt0.7Cu0.3: A Critical Ferro–Antiferromagnetic Compound Studied under Pressure

“…In metallic systems where RKKY interactions are the basis of the magnetic behaviour, simple modifications in the rare earth or in the d metal atoms involve the change from ferro (FM) to antiferromagnetic (AFM) behaviour. In a broad, in-depth study on RE-Ni/Pt-Cu compounds where only RE carry magnetic moment 1 , it can be concluded that these changes are driven by the induced changes on the conduction band, in particular on the density of states on the Fermi level N(E F ). Straightforward evidence of such assertions is the comparison between the REPt 1-x Cu x and the RENi 1-x Cu x series.…”