Using dc and ac magnetometry, the pressure dependence of the magnetization of the threedimensional antiferromagnetic coordination polymer Mn(N(CN)2)2 was studied up to 12 kbar and down to 8 K. The antiferromagnetic transition temperature, TN, increases dramatically with applied pressure (P ), where a change from TN(P = ambient) = 16.0 K to TN(P = 12.1 kbar) = 23.5 K was observed. In addition, a marked difference in the magnetic behavior is observed above and below 7.1 kbar. Specifically, for P < 7.1 kbar, the differences between the field-cooled and zero-field-cooled (fc-zfc) magnetizations, the coercive field, and the remanent magnetization decrease with increasing pressure. However, for P > 7.1 kbar, the behavior is inverted. Additionally, for P > 8.6 kbar, minor hysteresis loops are observed. All of these effects are evidence of the increase of the superexchange interaction and the appearance of an enhanced exchange anisotropy with applied pressure.

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The light-induced magnetization changes in cobalt ferrite nanoparticles are reinvestigated to probe the mechanism of photomagnetic behavior and to uncover the essential criteria required to observe the effect. Irradiation with white light results in pronounced demagnetization as evidenced by a decrease in the coercivity (ΔHc ∼ 3 kOe at 10 K) and a drop in the high field magnetization at 70 kOe. Wavelength dependent studies show the optical excitation driving the effect is broad in nature. Power and temperature (T) dependent measurements reveal strikingly different photomagnetic behaviors for the high field magnetization and coercive fields with energy scales of 25 K and 200 K, respectively. Importantly, the magnitude of the light-induced change in the magnetization is found to be specific to the synthesis protocol, with aggregated nanoparticles showing a larger effect than isolated particles. Mössbauer spectroscopy provides additional evidence of the differences between the aggregated and isolated nanoparticle samples. For T ≲ 25 K, the photo-response arises from magnetic disorder generated by an elevated electronic temperature in the surface layer of the particles, thereby leading to a decrease in magnetic volume. For 25 K ≲ T ≲ 200 K, the electronic and phononic reservoirs are more intimately coupled, so the photo-induced magnetic response follows the temperature dependence of the magneto-crystalline anisotropy. A similar response in manganese ferrite suggests that the mechanism is general.

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A novel multifunctional nanofluid composite of Iron oxide/Gold (Fe2O3-Au) was prepared using simple wet chemical method by reducing Chloroauric acid using trisodium citrate in the presence of Fe2O3 stock solution. The optical and morphological characterization confirmed the formation of hybrid structure of Iron Oxide with Gold nanoparticles. In-vitro cytoprotective studies of the sample was carried out in L929 cells. The study showed an increase up to 15% in the cell viability by the co-administration of 25 μL of Fe2O3-Au nanofluid in the L929 cells, which suffered significant reduction in cell viability due to laser irradiation. Thus, the sample is found to possess potential application in Photodynamic therapy.