The coercivity of the assembly is 400 Oe at 300 K and reaches 13 kOe at 1.9

K. Figure  6b shows the influence of the nanoparticle loading in the copolymer matrix to the saturation magnetization and remnant magnetization (M r). The increase in CFO phase content (as volume fraction) gives rise to a systematic increase in the overall Ms value; the non-magnetic P(VDF-HFP) polymer does not appear to inhibit the interactions of the magnetic Alvocidib polarization in individual nanocrystals. The composite films show the same coercivity, irrespective of the CFO content. Figure 6 Field-dependent magnetization hysteresis of CoFe 2 O 4 /P(VDF-HFP) nanocomposites. (a) With 30 wt.% CFO loading at various selleckchem temperatures and (b) at 300 K with various CFO weight

fraction. Inset, central region on an expanded scale. In order to verify the concerted interaction between the magnetic and ferroelectric phases, hysteresis loops of the CFO/PVP nanocomposites were recorded (Figure  7) and compared with those of the CFO/P(VDF-HFP), presented in Table  2. The saturation magnetization of PVP films are lower compared to PVDF-HFP films with the same composition over the entire magnetic field range. The differences are +1.36 and +2.97 emu/g for 10 and 50 wt.% CFO loading, respectively. The change of the M s values of the nanocomposite films was normalized for weight fraction and analyzed by the following equation: Figure 7 The hysteresis loops of 10 wt.% CFO/P(VDF-HFP) thin-films (a) and 50 wt.% CFO/PVP thin films (b). Table 2 Saturation magnetization Selleckchem BYL719 (M s ) and normalized percentage change of HSP90 saturation magnetization (Δ M s %) values for CFO/P(VDF-HFP) and CFO/PVP films with various CFO contents Sample M s(emu/g) ΔM s% P(VDF-HFP) films      10 wt.% CFO 8.0 +20.7%  30 wt.% CFO 21.8 +9.61%  50 wt.% CFO 36.0 +8.60% PVP films      10 wt.% CFO 6.6 +0.09%  30 wt.% CFO 20.2 +0.96%  50 wt.% CFO 33.0 −0.36% (4) where M s is the saturation magnetization of a film with certain CFO weight fraction, f is the corresponding

weight percentage, M s0 is the saturation magnetization of pure CFO, and ΔM s% is the normalized percentage change of the M s value of each polymer-based film relative to the comparative weighted, pure cobalt ferrite films. The ΔM s% values for both P(VDF-HFP) and PVP films are summarized in Table  2. The ΔM s% for the CFO/PVP films is close to zero for all three samples, indicating that the net magnetic moments of the thin films is equivalent to the sum of the contributions from each individual CFO grain inside the PVP matrix (volume fraction contribution only). In contrast, all CFO/P(VDF-HFP) films exhibit positive values of ΔM s%, with a gradual increase as the copolymer fraction increases.