Room temperature ferromagnetism in Fe-doped europium oxide (Eu1.90Fe0.10O3−δ)

Paramagnetic to ferromagnetic phase transition of Co doped Gd2O3 prepared by chemical route

“…Hazarika et al, reported the super paramagnetic behavior of Gd 2 O 3 nanorod at 300 K with maximum magnetization~6 emu/ gm at 6 T [33] whereas GCO exhibit paramagnetic nature with maximum magnetization at 300 K is~5.6 emu/gm at 5 T. Bandyopadhyay et al, reported the RTFM in Co doped Dy 2 O 3 [21] where the maximum magnetizations at 300 K and 10 K are~6.45 emu/gm at an applied field of~3 T and~110 emu/gm with maximum applied field of~5 T, respectively. Besides this work, Bandyopadhyay et al, reported the RTFM in Fe doped Eu 2 O 3 [22] where the maximum magnetizations at 300 K and 2 K are~1.93 emu/gm and~5.23 emu/ gm with maximum applied field of~5 T, respectively. Mandal et al, investigated the magnetic properties of Fe doped Sm 2 O 3 [23] where the maximum magnetizations at 300 K and 2 K are~0.2 emu/gm and~3.3 emu/gm, respectively with maximum applied field of~5 T and paramagnetic to ferromagnetic transition is observed at~30 K.…”

“…The sharp rise of magnetization below~30 K may be related with the weakly coupled or uncoupled TM ions. We could not fit the MeT curve of GCO by three-dimensional (3D) spin-wave model or by CurieeWeiss law independently below~30 K, but a combination of these two were used to fit the MeT curve below~30 K by the following fitting equation [22].…”

“…Due to high resistivity, high dielectric constant and large band gap of these systems, various physical viz., optical (absorption spectra, IR spectra, Raman spectra), magnetic, thermal and hyperfine properties of rare earth oxides have been extensively investigated [18e20]. Apart from TM-ion doped CeO 2 , the magnetic properties of Dy 1.90 Co 0.10 O 3 [21], Eu 1.90 Fe 0.10 O 3Àd [22], Sm 1.90 Fe 0.10 O 3 [23] and Sm 1.9 Co 0.1 O 3 [13] have investigated in recent years. Among different RE oxides, Gd 2 O 3 is also an important system as Gd 3þ is S-state ion with high value of free ion magnetic moment (~7.94 m B ) as well as high value of dielectric constant [17].…”

“…There are different mechanisms to explain the origin of observed room temperature ferromagnetism (RTFM) in the TM-ion doped semiconducting or insulating [15] oxides. Recently, we have shown the vacancy mediated RTFM in Co doped Dy 2 O 3 [21] and Fe doped Eu 2 O 3 [22]. The hightemperature FM obtained in TM-doped insulating oxides such as HfO 2 [5], CeO 2 [6], and La 2 O 3 [7] refers to an oxygen vacancy (Vo)-mediated FM mechanism [15].…”

XRD, HRTEM, Raman and magnetic studies on chemically prepared nanocrystalline Fe-doped gadolinium oxide (Gd1.90Fe0.10O3−δ) annealed in vacuum

“…In the family of RE oxides magnetic behavior of TM-ion doped CeO 2 have been extensively investigated. Besides this the magnetic properties of Dy 1.90 Co 0.10 O 3 , 14 Eu 1.90 Fe 0.10 O 3Àd , 15 Sm 1.90 Fe 0.10 O 3 16 and Sm 1.9 Co 0.1 O 3 11 have investigated in recent years. Recently, we have shown the oxygen vacancy mediated RTFM in Co doped Dy 2 O 3 14 and Fe doped Eu 2 O 3 .…”