Magnetic properties of (SrFe12O19) x (CaCu3Ti4O12)1–x composites

Magnetic properties of (La 0.7 Sr 0.3 MnO 3 ) x (CaCu 3 Ti 4 O 12 ) 1−x nanostructured composites

“…We suggest that below T < 210 K the influence of the ferromagnetic field of LSMO-component dominates over thermal vibrations of CCTO-phase, thus LSMO microinclusions "magnetizes" the paramagnetic CCTO leading to the decreasing of the integral intensity of the paramagnetic signal. A similar situation was observed in the case (SrFe 12 O 19 ) 0.05 (CaCu 3 Ti 4 O 12 ) 0.95 composites [12]. The linewidth of the ESR paramagnetic line larger than the value for pure CCTO ∆ H = 50-60 Oe at the temperature range 100 K < T < 300 K [38].…”

“…The additional coating of the LSMO particles by the NiFe 2 O 4 leads to the decreasing of the value of the saturation magnetization of composite particles and increasing of the coercive field at the same time relative to pure LSMO, owing to the ionic substitution at the interfaces of the core/shell structure and the increase of NiFe 2 O 4 content [10]. These experimental facts can be attributed to the magnetic proximity effects [11] as well as changes in the Curie temperature about 50 K in the case of (SrFe 12 O 19 ) 0.05 (CaCu 3 Ti 4 O 12 ) 0.95 composites [12]. Another example is given in [13], where Muscas et al compared the properties of a mechanical mixture (N-mix) of the La 0.67 Ca 0.33 MnO 3 and CoFe 2 O 4 phases with nanocomposites (NC) prepared by a new synthetic approach.…”

“…From Fig. 10 a we see that for these concentrations the resonance fields of the paramagnetic line decrease with decreasing the temperature together with ferromagnetic line in the range 210 K T 300 K. The decrease of the resonance fields for ferromagnetic line H f er res at 500 Oe in the temperature range 100-300 K and increasing of the linewidth in The absolute values of the resonance field of the paramagnetic line for the concentration x=0.01 correspond to the values of the pure CCTO H res =3250 Oe, where ESR spectra is due to Cu 2+ S=1/2 and is characterized by the g-factor g=2.15 [12,38]. For all other concentrations g-factor is less than g=2.15 (Fig.…”

Entanglement of cation ordering and manipulation of the magnetic properties through a temperature-controlled topotactic interface reaction in nanocomposite perovskite oxides

“…17,19,20 There are numerous studies that have shown modification of physical properties in correlated functional oxides nanocomposites. [21][22][23][24][25][26][27][28][29][30] The optimized interface between the hard (SrFe 12 O 19 ) and soft (CoFe 2 O 4 ) magnetic phases results from symbiotic grain growth, where one phase helps in the crystallization of the other one in the sol-gel process through the strong interfacial magnetic coupling between the two phases. 29 A decrease in a magnetic moment with an increase in the coercive field of La 0.7 Sr 0.3 MnO 3 is observed in the La 0.7 Sr 0.3 -MnO 3 /NiFe 2 O 4 core-shell structure.…”

“…22 The magnetic proximity effects and interface exchange interactions are reported to change the ferromagnetic T C by B50 K for SrFe 12 O 19 and La 0.7 Sr 0.3 MnO 3 in composite with CaCu 3 Ti 4 O 12 . 25 For oxide nanocomposite systems, the proper choice of a second phase can be used to tune the magnetic properties of the matrix. 27 A dramatic change in the magnetic properties of the multiferroic double perovskite La 2 MnCoO 6 in composite with CaCu 3 Ti 4 O 12 is observed due to local structural modification across the grain boundary.…”