Magnetic and electrical properties of RCo2Mn (R=Ho, Er) compounds

Abstract

The RCo2Mn (R= Ho and Er) alloys, crystallizing in the cubic MgCu2-type structure, are isostructural to RCo2 compounds. The excess Mn occupies both the R and the Co atomic positions. Magnetic, electrical and heat capacity measurements have been done in these comounds. The Curie temperature is found to be 248 K and 222 K for HoCo2Mn and ErCo2Mn respectively, which are considerably higher than that of the corresponding RCo2 compounds. Saturation magnetization values calculated in these samples are less compared to that of the corresponding RCo2 compounds. Heat capacity data have been fitted with the nonmagnetic contribution with Debye temperature =250 K and electronic coefficient=26 mJ mol^-1K^-2.Comment: 13 pages, 5 figures, 2 table

Tuning the magnetic and structural transitions in TbCo2Mnx compounds

“…The cubic Laves phases RT 2 (R = rare earth, T = transition metal) series magnetic materials were studied intensively because of their unique electronic and magnetic structures, which lead to many physical properties such as giant magnetocaloric effect, magnetoresisitance [1,2], and hydrogen storage capacity [3]. Typical Laves phases include the cubic C 15 (MgCu 2 ), hexagonal C 14 (MgZn 2 ), and hexagonal C 36 (MgNi 2 ) [3].…”

“…Wang et al [5,6] discovered RNi 2 Mn (R = Tb, Dy, Ho, Er) compounds, which crystallize in the cubic MgCu 2 -type structure (F d3 m, space group). Recently, it was reported that RCo 2 Mn with R = Ho and Er also crystallize in the cubic MgCu 2 -type structure [2]. It was found that the introduction of Mn into RT 2 (T is 3d or 4d transition metal) compounds led to a significant modification of magnetic properties such as the Curie temperature [2,4,[7][8][9][10][11], magnetic entropy change [4], saturation moment [2], the nature of the magnetic transition [4], and so on.…”

“…Recently, it was reported that RCo 2 Mn with R = Ho and Er also crystallize in the cubic MgCu 2 -type structure [2]. It was found that the introduction of Mn into RT 2 (T is 3d or 4d transition metal) compounds led to a significant modification of magnetic properties such as the Curie temperature [2,4,[7][8][9][10][11], magnetic entropy change [4], saturation moment [2], the nature of the magnetic transition [4], and so on. It is accepted that the Curie temperature can be raised significantly with Mn doping due to the enhanced 3d transition-metal ion interactions [5,6].…”

“…It is accepted that the Curie temperature can be raised significantly with Mn doping due to the enhanced 3d transition-metal ion interactions [5,6]. It is of interest that the RT 2 Mn compounds were isostructural to RT 2 with the * jianli@uow.edu.au † cheng@uow.edu.au MgCu 2 -type structure, although the ratio of the R to T is 1:3 [2,4,[7][8][9][10][11], and the Mn was observed to occupy both the R and T sites. All the above modified magnetic properties and crystal structure inspired more work on related series materials such as ErCo 2 Mn [2], HoNi 2 Mn [9], DyNi 2 Mn [5,6], and TbNi 2 Mn [6,7].…”

Magnetic phase transition and Mössbauer spectroscopy of ErNi2Mnx compounds

“…4 Such differences in the space group for TbNi 2 Mn indicate that the structural and magnetic properties of RNi 2 Mn compounds may be ultra sensitive to sample synthesis and heat-treatment conditions, 1-4 similar to the case in RNi 2 systems. 5 Quite recently, Maji et al 6 reported that the RCo 2 Mn (R ¼ Ho and Er) alloys also crystallize in the cubic MgCu 2type. Moreover, many attempts have been made to use experimental and theoretical atomic parameters to construct structural maps for various MgCu 2 -type (Fd-3m space group) compounds owing to their relatively simple crystal structure and outstanding magnetic properties.…”