Enhanced low-field magnetocaloric effect in Nb and Al co-substituted EuTiO3 compounds. (10th August 2022)

• Record Type: Journal Article
• Authors: Xie, Huicai; Su, Wenxia; Lu, Haiming; Mo, Zhaojun; Wang, Dunhui; Sun, Hao; tian, Lu; Gao, Xinqiang; Li, Zhenxing; Shen, Jun
• Is Part Of: Journal of materials science & technology. Volume 118(2022)
• Page Start: 128
• Page End: 135
• Publication Date: 2022-08-10
• Subjects: Magnetocaloric effect -- Europium titanate (EuTiO3) -- Ferromagnetic -- Magnetic refrigeration; Metals -- Periodicals; Materials science -- Periodicals; Materials science; Metals; Periodicals; 620.1105
• DOI: 10.1016/j.jmst.2022.02.005
• Languages: English
• ISSNs: 1005-0302

Abstract

Highlights: First-principle calculations indicate that Nb and Al co-substitution can significantly enhance the FM coupling in Eu(Ti, Nb, Al)O3 system. The ground state of EuTi0.875 Nb0.0625 Al0.0625 O3, EuTi0.8125 Nb0.125 Al0.0625 O3 and EuTi0.75 Nb0.125 Al0.125 O3 exhibit FM, which is consistent with the theoretical calculations. In a field change of 0-1 T, the magnetic entropy change of all compounds is larger than 15 Jkg −1 K −1, and the maximum refrigeration capacity reaches 88 Jkg −1 . Element co-substitution is proved to be an effective way to improve magnetocaloric effect. Abstract: The magnetic ground state switching between antiferromagnetic (AFM) and ferromagnetic (FM) states in EuTiO3 provides the feasibility of regulating its magnetic properties and magnetocaloric effect. First-principles calculations demonstrate that the magnetic ground states for EuTi0.875 Nb0.0625 Al0.0625 O3, EuTi0.8125 Nb0.125 Al0.0625 O3, and EuTi0.75 Nb0.125 Al0.125 O3 are FM coupling. Experimental results also exhibit the FM coupling domination in these compounds, accompanied by a significantly enhanced low magnetic field magnetocaloric effect. The maximum magnetic entropy change of all the samples surpasses 15 J kg −1 K −1 with a field change of 1 T, which is 1.4 times as large as that of bulk EuTiO3 . Especially, the maximum refrigerating capacity for EuTi0.8125 Nb0.125 Al0.0625 O3 compound is evaluated to be 88.1 J kg −1, more than three times of that of EuTiO3 . The remarkable magnetocaloric performances prove Nb and Al co-substituted EuTiO3 compounds to be competitive candidates for magnetic refrigeration in the liquid helium temperature regime.