Structural study and large magnetocaloric entropy change at room temperature of La_1−x□_xMnO₃ compounds

Abstract

In this study, our central focus is to investigate the magnetocaloric characteristics of a La1−x□xMnO3 (x = 0.1, 0.2 and 0.3) series prepared by a sol–gel technique.

Crystal structure, composition and valence state of cations in mixed-valence A1−xCdxMnO3 (A=Pr, La) ceramics

“…Manganese oxides with the perovskite structure are of great interest due to their physical properties which have significant potential for various applications [1][2][3][4][5][6][7][8][9][10]. For decades, steady interest has been focused on manganese compounds with a general formula A 1−x B x MnO 3 , where A is a rare earth element (La, Pr, Sm, Nb), and B, a divalent cation (Ca, Ba, Sr, Pb) [1,2].…”

“…The initial interest in these compounds stemmed from the discovery of a colossal magnetoresistance effect [3][4][5][6]. Later, a variety of intriguing magnetic and electrical effects were uncovered in these compounds [7][8][9][10][11][12][13][14][15][16], including the observation of both positive and negative temperature resistance coefficients [17], metal-insulator transitions [18], ferromagnetic-paramagnetic transitions [19,20], and charge ordering [21,22]. These properties make these materials promising for use in magnetic sensors [23], supercapacitors [24], and infrared bolometers [25,26].…”

Investigations on Strong-Tuned Magnetocaloric Effect in La0.5Ca0.1Ag0.4MnO3

“…Numerous research over decades have studied various magnetic materials to discover their suitability as magnetocaloric (MC) materials suitable for the MR industry (Hamad, 2015b;Masrour et al, 2017;Jebari et al, 2021;Labidi et al, 2021). It is preferable to use MC materials that have a magnetic transition type of the second degree with a suitable Curie temperature (θ C ) as appropriate for use in a wide temperature range, including room temperature (Choura-Maatar et al, 2020;Henchiri et al, 2020;Laajimi et al, 2020). The current efforts are directed towards the use of manganite as an effective substance in MRs due to its great chemical stability during frequent use, lack of eddy current, ease of preparation, high electrical resistance, and the possibility of improving their properties through doping and changing the oxygen content (Alzahrani et al, 2020;Choura-Maatar et al, 2020;Henchiri et al, 2020;Laajimi et al, 2020).…”

“…It is preferable to use MC materials that have a magnetic transition type of the second degree with a suitable Curie temperature (θ C ) as appropriate for use in a wide temperature range, including room temperature (Choura-Maatar et al, 2020;Henchiri et al, 2020;Laajimi et al, 2020). The current efforts are directed towards the use of manganite as an effective substance in MRs due to its great chemical stability during frequent use, lack of eddy current, ease of preparation, high electrical resistance, and the possibility of improving their properties through doping and changing the oxygen content (Alzahrani et al, 2020;Choura-Maatar et al, 2020;Henchiri et al, 2020;Laajimi et al, 2020). Felhi et al prepared La 0.5 Ca 0.1 Ag 0.4 MnO 3 (LCAMO) via the ceramic method and reported an increase in H ext and an increase in broad ferromagnetic (FM) phase transition of LCAMO covering room temperature under high H ext (Jeddi et al, 2020).…”

Investigation of the Critical Behavior, Magnetocaloric Effect and Hyperfine Structure in the Fe72Nb8B20 Powders

“…Many methods have been used to produce magnetocaloric materials such as mechanical alloying (MA) [19,20], solid state reactions [21], sol gel routes [22], melt spinning [23,24], etc. In the mechanically alloyed powders, the MCE response can be affected by several factors such as the alloy composition, the multiphase character, the demagnetizing field effect, etc.…”