Magnetovolume effect in ThMn12-type Fe-rich R(Fe,Nb)12-based compounds

Abstract

We have measured the thermal expansion of several Fe-rich compounds with the ThMn 12 structure. The series RFe 11.3 Nb 0.7 (R=Y, Sm, Gd, Tb, Dy, Ho and Er), Ho(Fe 1Àx Ni x ) 11.3 Nb 0.7 with x ¼ 020:3; YFe 11 Ti and YFe 10 Mo 2 have been investigated in the temperature range 150-800 K. In the Fe-rich compounds with stabilizing element T=Nb and Ti, a pronounced positive spontaneous volume magnetostriction has been observed below the Curie temperature. The effect of Ni substitution for Fe on the volume effect and on the Curie temperature has been analyzed studying the Ho(Fe 1Àx Ni x ) 11.3 Nb 0.7 compounds. The different magnitude of the magnetovolume effect observed in YFe 11.3 Nb 0.7 , YFe 11 Ti and YFe 10 Mo 2 is explained in terms of the classical model for itinerant ferromagnets. r

Anomalies in magnetoelastic properties of DyFe11.2Nb0.8 compound

“…Analysis of the DC magnetization data (not shown here) leads to the Curie temperature of T C ¼ 523(65) K with the two spin reorientation temperatures determined as T sr1 ¼ 202 (62) K and T sr2 ¼ 94(62) K. As reported in our earlier work, 10 there is strong magneto-structural coupling around T C in RFe 12Àx Nb x compounds where pronounced positive spontaneous volume magnetostriction has been observed below the Curie temperature. While Figure 1(b) reveals anomalies in the lattice parameters around both spin reorientation temperatures, these structural changes are less pronounced than those observed at T C .…”

“…While Figure 1(b) reveals anomalies in the lattice parameters around both spin reorientation temperatures, these structural changes are less pronounced than those observed at T C . 10 The structural changes around T sr1 ¼ 202 K and T sr2 ¼ 94 K are evident from the thermal expansion coefficients for DyFe 11.2 Nb 0.8 shown in Figure 1(c)). …”

Thermal expansion anomaly and magnetostriction of Nd2Fe14Si3 intermetallic compound

“…The anomalous thermal expansion and Invar effect in R 2 Fe 17 -type below room temperature is due to the negative magnetic interaction between the 6c-6c, 9d-18f, and 9d-18h sites [5]. Here, we calculate approximately J FeFe (Heisenberg Hamiltonian) for these sites as: [29,30]. Finally, the decrease of x s with temperature can be attributed to the decrease of the magnetic moment and the magnetic exchange interaction values with temperature increasing.…”

Influence of low Co substitution on magnetoelastic properties of HoFe11Ti intermetallic compound

“…In the past two decades, magnetic properties and magnetic structure of RFe 11 Ti have been studied in order to investigate the nature of the field-induced magnetic phase transitions [5][6][7]. Many researches have also been performed on the investigation of magnetoelastic properties of intermetallic compounds based on RFe 12 À x M x [8][9][10][11][12]. In the previous study, we investigated the structural and magnetic properties of HoFe 11 À x Co x Ti compounds [13].…”