The equiatomic region of the Mn-Ni system

Coles, B.R.

doi:10.1007/bf02664846

Cited by 10 publications

(9 citation statements)

References 5 publications

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“…1. The presently determined phase boundaries are in reasonable agreement with those determined from microscopical methods by Coles 3,5 and by differential thermal analysis methods by Tsiuplakis. 4 When compared with the phase diagram as determined by Coles, the B2 single phase field shifts about 1 at.…”

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confidence: 83%

Thermodynamic stability and diffusivity of near-equiatomic Ni–Mn alloys

Ding

Ladwig

Yan

et al. 2002

Applied Physics Letters

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The equilibrium phase diagram of the nickel-manganese system is determined between 500 and 850°C, in the composition range between 25 and 70 at. % Ni. A combination of electron probe microanalysis, x-ray diffraction, and optical microscopy was employed to analyze 47 samples that were annealed anywhere from three to seven months. The equiatomic, antiferromagnetic, L1 0 -NiMn phase that is of considerable technological interest was found to exist continuously between 500 and 700°C. No other intermediate phases were found in this study at low temperatures. These results are in contrast to the currently accepted phase diagram published in most handbooks. A hot-isobaric-pressing method was used to initially bond samples that were subsequently used to determine interdiffusion coefficients in the Ni-Mn system at 650°C. The Boltzmann-Matano method ͓T. Heumann, Z. Phys. Chem. 201, 168 ͑1952͔͒ allowed the calculation of these interdiffusion coefficients across the ␣-Mn, ␤-Mn, ␥-Mn, Equiatomic Ni-Mn thin films are of interest to the magnetic storage industry for use in magnetoresistive sensors. 1 In these sensors, exchange coupling between an antiferromagnetic film, such as NiMn, and a soft ferromagnetic film is required to hold or ''pin'' the magnetization within the ferromagnetic layer. 1 However, the L1 0 phase of NiMn is the only antiferromagnetic phase of this intermetallic, and is thus the only phase suitable for use in these sensors. Therefore, understanding the compositional and temperature ranges over which this antiferromagnetic phase is stable is extremely important but is made very difficult due to the vast inconsistencies between published equilibrium phase diagrams. Furthermore, there is no existing diffusion coefficient information for Ni-Mn alloys in the equiatomic range. Diffusion coefficient information is of significant importance because interlayer diffusion is a primary long-term failure mechanism in magnetoresistive sensors. In the present study, we apply information gained from experiments to resolve the controversy between existing phase diagrams as well as report reliable diffusion coefficients for NiMn alloys.NiMn exists in three solid polymorphic phases at the equiatomic concentration: a high-temperature ͑H͒, chemically disordered, face-centered-cubic ͑fcc͒ A1 phase; a midtemperature ͑M͒, chemically ordered, cubic B2 phase; and a low-temperature ͑L͒, antiferromagnetic, chemically ordered, tetragonal L1 0 phase. 2 The L1 0 structure is simple tetragonal with a two atom basis that resembles a nonBravais, body/face-centered-tetragonal structure. Although all previously published phase diagrams report the existence of these three phases, their reported equilibria are drastically different. For example, the phase diagram as determined by Coles and Hume-Rothery 3 shows a L1 0 phase that is stable from room temperature to 700°C, while Tsiuplakis and Kneller 4 reported a much more complicated phase diagram which claims that no single phase is stable at the equiatomic composition between 480 and 620°C. Th...

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confidence: 83%

Thermodynamic stability and diffusivity of near-equiatomic Ni–Mn alloys

Ding

Ladwig

Yan

et al. 2002

Applied Physics Letters

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“…Recently, Coles [10] reinvestigated the equiatomic region of the Mn-Ni system and stated that it is impossible to have so many stable phases suggested by Tsiuplakis and Kneller [6] at the equiatomic compositon between 480 and 630 8C. In Coles's experimental work [10] all three samples annealed for three months at 500, 525, and 565 8C showed only the lines of the tetragonal CuAuI structure and the behavior below 700 8C in the Ni-rich 0966 [8]. Ding et al [11] also considered that only one phase existed in the equiatomic region between 500 and 650 8C.…”

Section: Experimental Informationmentioning

confidence: 99%

“…Based on the above experimental results especially the phase diagram measured by Tsiuplakis and Kneller [6], the Mn-Ni system was reviewed by Gokcen [9]. Recently, Coles [10] reinvestigated the equiatomic region of the Mn-Ni system and stated that it is impossible to have so many stable phases suggested by Tsiuplakis and Kneller [6] at the equiatomic compositon between 480 and 630 8C. In Coles's experimental work [10] all three samples annealed for three months at 500, 525, and 565 8C showed only the lines of the tetragonal CuAuI structure and the behavior below 700 8C in the Ni-rich 0966 [8].…”

Section: Experimental Informationmentioning

confidence: 99%

Thermodynamic optimization of the Mn–Ni system

Guo

2005

Intermetallics

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“…Tsiuplakis and Kneller [17] investigated the Mn-Ni system in detail, in which eight intermetallic compounds Mn 3 Ni, Mn 2 Ni, MnNi(g), MnNi(g 0 ), MnNi(g 00 ), MnNi 2 (n), MnNi 2 (n 0 ), and MnNi 3 were found. Later, Coles [18] reinvestigated the equiatomic region of the Mn-Ni system and stated that it is impossible to have so many stable phases suggested by Tsiuplakis and Kneller [17] at the equiatomic composition between 480 and 630°C. In Coles's [18] and Ding's experiment [20], only one phase existed in the equiatomic region between 500°C and 650°C.…”

Section: Introductionmentioning

confidence: 99%

“…The most reliable Ni-Mn [17][18][19][20], Mn-In [21] and Ni-In [22,23] phase diagrams have been published. The phase diagram of the NiMn system was early investigated by many groups.…”

Section: Introductionmentioning

confidence: 99%

Isothermal section of the Ni–Mn–In ternary system at 773 K

Liu

et al. 2015

Journal of Alloys and Compounds

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The equiatomic region of the Mn-Ni system

Cited by 10 publications

References 5 publications

Thermodynamic stability and diffusivity of near-equiatomic Ni–Mn alloys

Thermodynamic stability and diffusivity of near-equiatomic Ni–Mn alloys

Thermodynamic optimization of the Mn–Ni system

Isothermal section of the Ni–Mn–In ternary system at 773 K

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