Evidence of non-stoichiometry effects in nanometric manganite perovskites: influence on the magnetic ordering temperature

Improving the crystallinity and magnetocaloric effect of the perovskite La0.65Sr0.35MnO3 using microwave irradiation

“…72 Thus the increase of approximately 60 % in the zero-field cooled magnetic susceptibility (between LSMO35-Con and LSMO35-MW) shown in Figure 9 can be rationalised by increasing ferromagnetic contribution associated with the improvement in crystallinity, but also suggests reduced cluster formation and greater ordering of magnetic domains also. 6 This was previously suggested by Epherre et. al who proposed that the reduced proportion of magnetic clusters (as also seen in Section 3.1 in this work), could lead to fewer local distortions within the particle cores, in turn increasing the saturation magnetisation (Ms) (and magnetic susceptibility) which is seen in this work.…”

“…al who proposed that the reduced proportion of magnetic clusters (as also seen in Section 3.1 in this work), could lead to fewer local distortions within the particle cores, in turn increasing the saturation magnetisation (Ms) (and magnetic susceptibility) which is seen in this work. 6 Figure 9 also shows that all samples undergo a ferromagnetic to paramagnetic transition with little difference in the transition temperature (2 K) with Tc's of 362 K for LSMO35-Con and 360 K (reported in Table 4) for all of the samples synthesised using MW-irradiation (LSMO35-50W, LSMO35-100W and LSMO35-200W). Tc's were obtained using the Arott plot method, where the inverse of magnetic susceptibility is plotted against the square of magnetisation with respect to temperature (Supplementary Figure S12).…”

“…For example, La0.9Sr0.1MnO3 has a Tc of -13 °C which increases to 77 °C for La0.8Sr0.2MnO3. 6 Previous studies which have illustrated the tunable structureproperty relationship of LSMO perovskites have mainly investigated the effect of altering composition 6,[30][31][32] or particle size 33 on the magnetic properties of the LSMO crystallite clusters. It has also been shown that the actual method of synthesis employed will affect the physical properties such as the electrical conductivity of the material.…”

“…[4][5][6][7][8] The therapeutic use of heat between 41 °C and 46 °C is known as 'Mild Hyperthermia'. 9 In this temperature range, the treatment can selectively target and damage the cancerous tissue, leaving normal tissue intact ( Figure 1).…”

Synthesis, characterisation and study of magnetocaloric effects (enhanced and reduced) in manganate perovskites

“…For example, increasing the dopant from x = 0.1 to 0.2 increases the Tc from -13 °C to 77 °C. 9 This change in Tc with structure meant that LSMO at a variety of dopant levels exhibited enhanced magnetic heating properties compared with the parent compound. 8 Figure 1(a) and (c) show the effect of substituting the A-site cation, La 3+ (cationic radii of 1.36 Å) with smaller (Ca 2+ ) or larger (Sr 2+ or Ba 2+ ) cations (cationic radii of 1.34, 1.44 or 1.61 Å respectively) 10 on the structure of the parent perovskite unit cell (1b).…”