Magnetocaloric effect, electric, and dielectric properties of Nd0.6Sr0.4MnxCo1−xO3 composites

Abstract

The magnetocaloric effect (MCE) and electric-dielectric properties of the Nd-cobaltate perovskites Nd 0.6 Sr 0.4 Co 1Àx Mn x O 3 (x = 0, 0.3, 0.7 and 1) were investigated for possible use in magnetic cooling applications. Upon Mn substitution, the magnetic exchange interaction is affected by the (Mn 4+ /Mn 3+) ratio, which in turn impacts several physical properties. The XRD patterns of the synthesized composites revealed a single phase with an orthorhombic structure with space group Pbnm (62). The orthorhombic lattice distortion increases linearly with the Mn content, reaching a maximum value (D = 7.377 Â 10 À3) for Nd 0.6 Sr 0.4 MnO 3. The temperature and frequency dependence of the dielectric permittivity was studied and analyzed using Maxwell-Wagner interfacial polarization and Koops phenomenological theory. The rapid increase in magnetic susceptibility around the paramagnetic (PM)-ferromagnetic (FM) transition temperature T C is greatly affected by Mn substitution. The decrease in susceptibility with increasing temperature can be attributed to a charge ordering effect. The PM-FM transition occurs in the temperature range of 150-200 K. Moreover, the presence of spontaneous magnetization with second-order phase transitions is observed from Arrott plot isotherms. The MCE was also investigated by determining DS M and the relative cooling power (RCP), and the maximum value is found for Nd 0.6 Sr 0.4 Co 0.3 Mn 0.7 O 3. These results compare favorably with those reported for similar materials, indicating our materials as a possible candidate for use in magnetocaloric refrigerators.

Doping Strontium into Neodymium Manganites Nanocomposites for Enhanced Visible light Driven Photocatalysis

“…Rare earth perovskites ABO 3 are used recently as photocatalysis 1–5 and these class of materials are key type of oxides due to their unusual physical and chemical properties 6–10 . The effect of nanocrystalline size is an efficient parameter that plays key role in these physical and the chemical properties showed by such materials 11–14 . The position of oxygen atoms around both transition metal cations A and rare earth cations B in the ABO 3 perovskites reflects how its importance role in determination its exciting properties and thus its potential applications.…”

“…The methods of synthesis play an important role in the formation of the required crystal structure and how the oxygen atoms in the octahedral are distributed beside the crystalline size. A lot of research work has been devoted to study photocatalysis performance of perovskite-like materials such as tantalate 26–29 , titanate 30–33 , ferrite 15–17 , vanadium and niobium 34–37 , and manganites 11–13 . These materials have displayed visible light photocatalytic activity because they have exclusive electronic properties, which correlated with their rich crystal structures 38–42 .…”

Role of B-site cation on the structure, magnetic and dielectric properties of nanosized La0.7Sr0.3Fe1−xMxO3 (M = Mn; Co and x = 0, 0.5) perovskites

“…The decrease of dielectric constant at higher frequencies region takes place in many steps, these different steps may arise from contributions of the electrode, grains, and grain boundaries. The dielectric behavior of these samples at low frequency can be described by the Maxwell-Wagner extrinsic interfacial model [15,30,31]. According to this model, the dispersion at low frequencies attributed to the interfacial polarization and the presence of depletion layers near the sample electrode contacts.…”

Analisis Struktur Kristal dan Sifat Kemagnetan Material Komposit Perovskite Manganit Nd0,6Sr0,4MnO3/ZnO

“…Sampai dengan penambahan komposisi x = 0,7 nilai magnetisasi masih berkurang menjadi 1 emu/g. Material NSMO bersifat paramagnetik saat diberikan medan magnet sebesar 2 T di suhu ruangan dengan nilai magnetisasi antara 0 -10 emu/g [7][8] [9]. Hasil magnetisasi menunjukkan bahwa kehadiran material ZnO dapat mengurangi nilai magnetisasi pada material komposit (NSMO)1-x/(ZnO)x. Hal ini dialami juga oleh Navin et al dengan menggunakan material komposit yang sama (ZnO) pada LSMO.…”