Vacancy mediated room temperature ferromagnetism in Co-doped Dy2O3

Abstract

Amorphous Slater-Pauling like behaviour in magnetic nanoparticles alloys synthesized in liquids J. Appl. Phys. 112, 063910 (2012) On the influence of nanometer-thin antiferromagnetic surface layer on ferromagnetic CrO2 J. Appl. Phys. 112, 053921 (2012) Thermal stability and the magnetic properties of hybrid vanadium oxide-tetradecylamine nanotubes J. Appl. Phys. 112, 053912 (2012) Nanostructured thin manganite films in megagauss magnetic field

Magnetic measurements, Raman and infrared spectra of metal–ligand complex derived from $$\hbox {CoCl}_{2}\cdot \hbox {6H}_{2}\hbox {O}$$ CoCl 2 · 6H 2 O

“…The negative value does not indicate the presence of any antiferromagnetic interaction of the Co-cations in the complex. This negative value of θ is mainly due to the crystal field effect, which is also found in different cases of our earlier studies [23,24].…”

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

“…Thus, it is inferred that the enhancement in magnetization in case of 5% Co doped Gd 2 O 3 compared to 5% Tb doped Gd 2 O 3 may be attributed to the presence of oxygen vacancy formed by sintering the sample in vacuum. 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.…”

“…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].…”

A thermomagnetic analysis of an eco-friendly nano-sized dysprosia for energy efficient cryo-cooling systems

“…Over the past decades, novel oxide materials have gained importance in cryogenic and room temperature cooling applications (Kumar et al 2019(Kumar et al , 2020Jaison et al 2020;Kumar and Meenakshi and Rabindra Mahato 2019). Rare earth oxides (REO) materials are of prominent technological interest in the field of refrigeration due to their capability to undergo isothermal entropy change when some external stimulus such as electric field, magnetic field, stress or pressure is applied (Singh et al 2006;Bandyopadhyay et al 2012;. The MCE of Dy 2 O 3 was studied at cryogenic temperatures by D-H Kim et al, who found that Dy 2 O 3 had an entropy change of about 18.2 J/ kgK at an applied magnetic field of 6 T (Shinde et al 2020).…”