Reentrant ferromagnetism observed in SmMn2Ge2

Fujii, H.; Okamoto, Tetsuhiko; Shigeoka, T.; Iwata, N.

doi:10.1016/0038-1098(85)90385-0

Cited by 189 publications

(106 citation statements)

References 5 publications

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“…The intermetallic compound SmMn 2 Ge 2 with its interesting magnetic properties has been a subject of intensive study during last two decades [1][2][3][4][5][6][7][8][9][10]. In low applied magnetic fields it shows at least three magnetic transitions as a function of temperature [1][2][3]6,7].…”

Section: Typeset Using Revt E Xmentioning

confidence: 99%

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Interesting thermomagnetic history effects in the antiferromagnetic state of SmMn₂Ge₂

Roy

Chaudhary

Chattopadhyay

et al. 2002

J. Phys.: Condens. Matter

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We present results of magnetization measurements showing that the magnetic response of the antiferromagnetic state of SmMn 2 Ge 2 depends on the path used in the field(H)-temperature(T) phase space to reach this state. Distinct signature of metastablity is observed in this antiferromagnetic state when obtained via field-cooling/field-warming paths. The isothermal M-H loops show lack of end-point memory, reminiscent of that seen in metastable vortex states near the field-induced first order phase transition in various type-II superconductors. Typeset using REVT E X 1The intermetallic compound SmMn 2 Ge 2 with its interesting magnetic properties has been a subject of intensive study during last two decades [1][2][3][4][5][6][7][8][9][10]. In low applied magnetic fields it shows at least three magnetic transitions as a function of temperature [1][2][3]6,7].First it undergoes a paramagnetic (PM) to ferromagnetic (FM1) transition at around 350K, followed by an FM1 to antiferromagnetic (AFM) transition at around 160 K (T N 1 ). On reduction of the temperature further this AFM state transforms again into another ferromagnetic (FM2) state around 100 K(T N 2 ). There is a large spread in the reported values of the transition temperatures from FM1 to AFM and AFM to FM2 states. Quality of the samples may be a possible source for the reported differences in the transition temperatures, especially when it is known that the microscopic magnetic properties of RE(rareearth)1-2-2 compomuds are quite sensitive to their underlying crystal lattice structure. On the other hand, there exist now enough evidences from various studies that both of these transitions are probably first order in nature [2,4,11,12]. The first order nature of these magnetic phase transitions can also provide a natural explanation to the reported spread in the transition temperatures. Supercooling(superheating) can take place down(up) to a temperature T * (T * * ) while cooling (heating) across a first order transition point (T N ) [13]. The extent of supercooled/superheated phases will depend on the path followed in the field(H)-temperature(T) phase space [14]. In addition in the samples with defect structures the lower(higher) temperature phase will start nucleating around these defect structures once the sample is cooled(heated) across T N . This nucleation of the lower(higher) T phase will be completed at T * (T * * ), and in the temperature regime T N -T * (T * * -T N ) there will be co-existence of two phases. All these properties will give rise to thermal hysteresis, and such thermal hysteresis is actually observed across the FM2-AFM and AFM-FM1 phase transitions in SmMn 2 Ge 2 [2,4,7].Confined between two FM phase at low and high temperature and reached via first order phase transitions, the AFM phase in SmMn 2 Ge 2 is something special. In this paper, based on our careful dc magnetization studies we shall show that the magnetic response of this AFM state actually depends on the path used in the (H,T) phase space to reach 2 this state. Distinc...

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Section: Typeset Using Revt E Xmentioning

confidence: 99%

“…In low applied magnetic fields it shows at least three magnetic transitions as a function of temperature [1][2][3]6,7].…”

Section: Typeset Using Revt E Xmentioning

confidence: 99%

Interesting thermomagnetic history effects in the antiferromagnetic state of SmMn₂Ge₂

Roy

Chaudhary

Chattopadhyay

et al. 2002

J. Phys.: Condens. Matter

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“…At atmospheric pressure SmMn2Ge 2 is a re-entrant ferromagnet [1][2][3][4][5]. The phase diagram is shown in Fig.…”

Section: Introductionmentioning

confidence: 99%

“…~-The change from ferromagnetism to antiferromagnetism of SmMn2Ge 2 below 150 K at atmospheric pressure was attributed [1] to the Mn-Mn spacing 100 dropping below a critical distance for ferromagnetic interactions. (The Sm magnetisation is not thought to be significant at 150 K.) This view is supported by the positive slope of dTN/dP [2,3], and the observation of 0 a first order decrease in the lattice constant along the * Corresponding author.…”

Section: Introductionmentioning

confidence: 99%

“…a-axis in the antiferromagnetic region [2]. The reversion of SmMn2Ge 2 to the ferromagnetic state below 100 K was attributed [1] to ferromagnetic ordering of the Sm causing the Mn movements to align ferromag- netically. However, the entropy change at the first order transition [2] is only (R/10)In 2 which makes this mechanism doubtful and the present NMR results also do not support it.…”

Section: Introductionmentioning

confidence: 99%

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NMR of SmMn2Ge2 at high pressure

Lord

Riedi

Kapusta

et al. 1995

Physica B: Condensed Matter

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The 1475m, 149Sm and SSMn NMR of SmMn2Ge 2 has been observed at 4.2 K at pressures up to 6.5 kbar. The Sm resonance frequencies appear to be insensitive to pressure but the Mn frequency decreases under pressure. The Mn resonance has also been observed at 77 K at atmospheric pressure, but disappears under a pressure of 1.6 kbar in agreement with the phase boundary between FM and AFM proposed earlier.

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Investigation of Magnetic Properties of NdMn2—xCoxGe2 Compounds (x = 0 to 1.0)

Wang

Chen

et al. 1997

phys. stat. sol. (a)

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Reentrant ferromagnetism observed in SmMn2Ge2

Cited by 189 publications

References 5 publications

Interesting thermomagnetic history effects in the antiferromagnetic state of SmMn₂Ge₂

Interesting thermomagnetic history effects in the antiferromagnetic state of SmMn₂Ge₂

NMR of SmMn2Ge2 at high pressure

Investigation of Magnetic Properties of NdMn2—xCoxGe2 Compounds (x = 0 to 1.0)

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Reentrant ferromagnetism observed in SmMn2Ge2

Cited by 189 publications

References 5 publications

Interesting thermomagnetic history effects in the antiferromagnetic state of SmMn2Ge2

Interesting thermomagnetic history effects in the antiferromagnetic state of SmMn2Ge2

NMR of SmMn2Ge2 at high pressure

Investigation of Magnetic Properties of NdMn2—xCoxGe2 Compounds (x = 0 to 1.0)

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Interesting thermomagnetic history effects in the antiferromagnetic state of SmMn₂Ge₂

Interesting thermomagnetic history effects in the antiferromagnetic state of SmMn₂Ge₂