Giant magnetocaloric effect in magnetoelectric Eu1-xBaxTiO3

Rubi, Km; Kumar, Pawan; Repaka, D. V. Maheswar; Chen, Ruofan; Wang, Jian‐Sheng; Mahendiran, R.

doi:10.1063/1.4862981

Cited by 36 publications

(21 citation statements)

References 26 publications

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“…2(a). A qualitatively similar behavior has been observed in polycrystalline Eu 1−x Ba x TiO 3 for 0.1 x 0.9 compounds [14]. Below T N , M varies almost linearly with magnetic field up to a critical field H C , above which it shows a tendency to saturate.…”

Section: Resultssupporting

confidence: 61%

“…Table I. EuO and DyTiO 3 have a magnetic ordering temperature above 40 K. It can be noted that T ad observed in EuTiO 3 is higher than other promising magnetocaloric materials for refrigeration from 1 to 40 K [14,[22][23][24][25][26][27][28][29]. Only the metal-organic framework material Gd(HCOO) 3 shows a comparable value [29].…”

Section: S(ht )| From S(0t) Isothermally Finally T Ad Is Obtainmentioning

confidence: 92%

“…It is also unique among the rare earth titanates (RTiO 3 , where R is the rare earth ion) because only the Eu 2+ ion adopts a divalent state instead of a trivalent state that is adopted by other rare earth ions (R = Gd,Y, etc.). Recently, polycrystalline samples of Eu 1−x Ba x TiO 3 (0.1 x 0.9) [14], EuTiO 3 [15], and EuTi 1−x Cr x O 3 [16] were studied from the perspective of the magnetocaloric effect and were found to show a huge isothermal magnetic entropy change ( S ∼ 45−40 J kg −1 K −1 for x = 0.0−0.1), as estimated from magnetization isotherms. It is of paramount importance that a good magnetic refrigerant possess not only a large S value, but also a large adiabatic temperature change ( T ad ) and refrigeration capacity (RC) in relative low magnetic fields.…”

Section: Introductionmentioning

confidence: 99%

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Large adiabatic temperature and magnetic entropy changes inEuTiO3

et al. 2016

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We have investigated the magnetocaloric effect in single and polycrystalline samples of quantum paraelectric EuTiO 3 by magnetization and heat capacity measurements. Single crystalline EuTiO 3 shows antiferromagnetic ordering due to Eu 2+ magnetic moments below T N = 5.6 K. This compound shows a giant magnetocaloric effect around its Néel temperature. The isothermal magnetic entropy change is 49 J kg −1 K −1 , the adiabatic temperature change is 21 K, and the refrigeration capacity is 500 J kg −1 for a field change of 7 T at T N . The single crystal and polycrystalline samples show similar values of the magnetic entropy and adiabatic temperature changes. The large magnetocaloric effect is due to suppression of the spin entropy associated with the localized 4f moment of Eu 2+ ions. The giant magnetocaloric effect, together with negligible hysteresis, suggest that EuTiO 3 could be a potential material for magnetic refrigeration below 40 K.

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Section: Resultssupporting

confidence: 61%

Section: S(ht )| From S(0t) Isothermally Finally T Ad Is Obtainmentioning

confidence: 92%

Section: Introductionmentioning

confidence: 99%

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Large adiabatic temperature and magnetic entropy changes inEuTiO3

et al. 2016

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“…MC increases almost linearly with H and reaches 700 J kg −1 for a field change of 9 T. The observed value of ∆S m for the present system is comparable with that for the AFM EuTiO 3 and Eu 1−x Ba x TiO 3 systems. 15,16 In these compounds also the position of maximum in ∆S m (T) curve is field independent and it occurs at T N . However, the value of ∆S m for EuTi 0.85 Nb 0.15 O 3 is significantly larger than that reported for several other rare-earth titanates 17 and Eu-based compounds including EuO and Eu 3 O 4 .…”

Section: +mentioning

confidence: 99%

Giant low-field magnetocaloric effect in single-crystalline EuTi0.85Nb0.15O3

2016

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The magnetocaloric effect in ferromagnetic single crystal EuTi0.85Nb0.15O3 has been investigated using magnetization and heat capacity measurements. EuTi0.85Nb0.15O3 undergoes a continuous ferromagnetic phase transition at TC = 9.5 K due to the long range ordering of magnetic moments of Eu2+ (4f7). With the application of magnetic field, the spin entropy is strongly suppressed and a giant magnetic entropy change is observed near TC. The values of entropy change ΔSm and adiabatic temperature change ΔTad are as high as 51.3 J kg−1 K−1 and 22 K, respectively, for a field change of 0–9 T. The corresponding magnetic heating/cooling capacity is 700 J kg−1. This compound also shows large magnetocaloric effect even at low magnetic fields. In particular, the values of ΔSm reach 14.7 and 23.8 J kg−1 K−1 for field changes of 0–1 T and 0–2 T, respectively. The low-field giant magnetocaloric effect, together with the absence of thermal and field hysteresis makes EuTi0.85Nb0.15O3 a very promising candidate for low temperature magnetic refrigeration.

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“…It was confirmed to be a multiferroic material used to search for the permanent electric dipole moment of the electron 13 . The compounds of Eu1-xBaxTiO3-family exhibit giant magnetocaloric effect, indicating that these compounds could be potential candidates for cryogenic magnetic refrigeration 14 .…”

Section: Introductionmentioning

confidence: 99%

Tailoring the structure and thermoelectric properties of BaTiO₃via Eu²⁺ substitution

Xiao

Widenmeyer

Xie

et al. 2017

Phys. Chem. Chem. Phys.

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A series of BaEuTiO (0.1 ≤ x ≤ 0.9) phases with ∼40 nm particle size were synthesized via a Pechini method followed by annealing and sintering under a reducing atmosphere. The effects of Eu substitution on the BaTiO crystal structure and the thermoelectric transport properties were systematically investigated. According to synchrotron X-ray diffraction data only cubic perovskite structures were observed. On the local scale below about 20 Å (equal to ∼5 unit cells) deviations from the cubic structure model (Pm3[combining macron]m) were detected by evaluation of the pair distribution function (PDF). These deviations cannot be explained by a simple symmetry breaking model like in EuTiO. The best fit was achieved in the space group Amm2 allowing for a movement of Ti and Ba/Eu along 〈110〉 of the parent unit cell as observed for BaTiO. Density functional calculations delivered an insight into the electronic structure of BaEuTiO. From the obtained density of states a significant reduction of the band gap by the presence of filled Eu 4f states at the top of the valence band was observed. The physical property measurements revealed that barium-europium titanates exhibit n-type semiconducting behavior and at high temperature the electrical conductivity strongly depended on the Eu content. Activation energies calculated from the electrical conductivity and Seebeck coefficient data indicate that at high temperatures (800 K < T < 1123 K) the conduction mechanism of BaEuTiO (0.1 ≤ x ≤ 0.9) is a polaron hopping when 0 < x ≤ 0.6 and is a thermally activated process when 0.6 < x < 1. Besides, the thermal conductivity increases with increasing Eu concentration. Due to a remarkable improvement of the power factor, BaEuTiO showed a ZT value of 0.24 at 1123 K.

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Giant magnetocaloric effect in magnetoelectric Eu_1-xBa_xTiO₃

Cited by 36 publications

References 26 publications

Large adiabatic temperature and magnetic entropy changes inEuTiO3

Large adiabatic temperature and magnetic entropy changes inEuTiO3

Giant low-field magnetocaloric effect in single-crystalline EuTi0.85Nb0.15O3

Tailoring the structure and thermoelectric properties of BaTiO₃via Eu²⁺ substitution

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Giant magnetocaloric effect in magnetoelectric Eu1-xBaxTiO3

Cited by 36 publications

References 26 publications

Large adiabatic temperature and magnetic entropy changes inEuTiO3

Large adiabatic temperature and magnetic entropy changes inEuTiO3

Giant low-field magnetocaloric effect in single-crystalline EuTi0.85Nb0.15O3

Tailoring the structure and thermoelectric properties of BaTiO3via Eu2+ substitution

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Giant magnetocaloric effect in magnetoelectric Eu_1-xBa_xTiO₃

Tailoring the structure and thermoelectric properties of BaTiO₃via Eu²⁺ substitution