Giant magnetocapacitance effect: (a) B-dependent magnetic permeability (μ_r) and delimited magnetic phase profile; (b) variable dielectric constant as a function of B field for the O₂ treated SrFe₁₂O₁₉ ceramics at a frequency of 100Hz and room temperature (300K).

<p>Giant magnetocapacitance effect: (a) B-dependent magnetic permeability (μ_r) and delimited magnetic phase profile; (b) variable dielectric constant as a function of B field for the O₂ treated SrFe₁₂O₁₉ ceramics at a frequency of 100Hz and room temperature (300K).</p

Modified Curie-Weiss law calculation.

<p>(a) Logarithm of (1/ε-1/ε_d) as a function of logarithm of (T-T_d) at 10 kHz. and (b) logarithm of (1/ε-1/ε_m) as a function of logarithm of (T-T_m) at 100 kHz for the SrFe₁₂O₁₉ ceramic being sintered at 1150°C for 1 hour and subsequently annealed in O₂ for 9 hours with 3 steps wise.</p

Valence band states assignment.

<p>Valence band states assignment.</p

Assembly of Multifunctionalized Gold Nanoparticles with Chemiluminescent, Catalytic, and Immune Activity for Label-Free Immunoassays

In this study, we report a universal label-free immunoassay to detect antigen based on multifunctionalized gold nanoparticles (MF-GNPs), which were obtained by successive assembly of <i>N</i>-aminobutyl-<i>N</i>-ethylisoluminol functionalized gold nanoparticles (ABEI-GNPs) with antibody, bovine serum albumin (BSA) and Co²⁺. MF-GNPs exhibited excellent chemiluminescent (CL), catalytic and immune activity. It was demonstrated that the CL signal of MF-GNPs decreased in the presence of antigens via antigen–antibody specific binding using human immunoglobulin G (hIgG) and corresponding antibody goat anti-human IgG (anti-hIgG) as a model system, due to that immunoreaction led to the aggregation of GNPs. According to the decreased CL intensity, hIgG could be determined in the range of 1.0 fM to 1.0 nM with a low detection limit of 0.13 fM. Furthermore, this CL strategy was also confirmed to be a general one by replacing hIgG with heart-type fatty acid-binding protein (H-FABP), which is a biomarker of early acute myocardial infarction (AMI). The CL strategy could be employed to detect H-FABP ranging from 10.0 fM to 10.0 nM, and the detection limit is 7.8 fM. The CL strategy also showed good selectivity. It might be extended to detect other antigens if their corresponding antibodies are available

Valence band spectra of SrFe₁₂O₁₉ ceramics (a) with O₂ heat treatment and (b) without O₂ heat treatment.

<p>The dotted lines marked the top of the valence band.</p

The equivalent circuit for the complex impedance of SrFe₁₂O₁₉ ceramics, the scheme is composed of two series linked sub-circuits with a capacitor and a resistor parallelly connected.

<p>The equivalent circuit for the complex impedance of SrFe₁₂O₁₉ ceramics, the scheme is composed of two series linked sub-circuits with a capacitor and a resistor parallelly connected.</p

Magnetoelectric Response in Multiferroic SrFe₁₂O₁₉ Ceramics - Fig 1

<p>(a) XRD pattern of SrFe₁₂O₁₉ with O₂ annealing process. (b) the standard diffraction pattern of the SrFe₁₂O₁₉(PDF#33–1340) being marked by discrete red lines.</p

(a) The saturated ferroelectric polarization hysteresis (P-E) loop, and (b) a plot of current as a function of voltage (I-V curve) of SrFe₁₂O₁₉ ceramic.

<p>The ceramic has been sintered at 1150°C for 1 hour and subsequently annealed at 800°C in pure oxygen for a total duration of 9 hours in 3 steps wise. The measurement was made at a frequency of 33Hz and room temperature (300K).</p

Plot of dielectric constant as a function of temperature for SrFe₁₂O₁₉ ceramics with O₂ treatment at frequencies of (a) 1kHz, (b) 10kHz and (c) 100 kHz.

<p>Plot of dielectric constant as a function of temperature for SrFe₁₂O₁₉ ceramics with O₂ treatment at frequencies of (a) 1kHz, (b) 10kHz and (c) 100 kHz.</p

Modules of the complex impedance for (a) the conventional SrFe₁₂O₁₉ ceramics being sintered at 1150°C in air only, (b) the sintered ceramic was subsequently annealed in pure oxygen atmosphere at 800°Cfor 3 hours, (c) the annealed ceramic was flipping over and once again heat treated in O₂at 800°C for another 3 hours.

<p>Modules of the complex impedance for (a) the conventional SrFe₁₂O₁₉ ceramics being sintered at 1150°C in air only, (b) the sintered ceramic was subsequently annealed in pure oxygen atmosphere at 800°Cfor 3 hours, (c) the annealed ceramic was flipping over and once again heat treated in O₂at 800°C for another 3 hours.</p