Detection of L-band electron paramagnetic resonance in the DPPH molecule using impedance measurements

Abstract

(a) Schematic diagram of our experimental set up. (b) Resistance and reactance of the DPPH molecule for 2 GHz current in the strip coil.

Electrically Detected Paramagnetic Resonance in Ag-Paint-Coated Polycrystalline DPPH

“…Δ H and H r are the linewidth and resonance fields for a particular frequency, respectively. A sym and A asym are the maximum amplitudes of the absorptive and dispersive components, respectively, and C is an offset constant . We obtain | A sym / A asym | = 10.451, which suggests that R is dominated by the symmetric component, whereas | A sym / A asym | = 9.790 × 10 –2 for the X -component, which indicates the line shape of X is mainly dominated by the dispersive component.…”

“…A sym and A asym are the maximum amplitudes of the absorptive and dispersive components, respectively, and C is an offset constant. 15 We obtain |A sym /A asym | = 10.451, which suggests that R is dominated by the symmetric component, whereas |A sym / A asym | = 9.790 × 10 −2 for the X-component, which indicates the line shape of X is mainly dominated by the dispersive component. The Lorentzian fits using eq 1 were performed on the R signals at five different frequencies, as shown in Figure 3a.…”

“…Broadband spectrometers are currently being developed that take advantage of powerful vector network analyzers to source MW signal over a wide range of frequencies (∼10 MHz to 40 GHz) and detect variation in the transmitted signal due to MW absorption by a sample placed either on a coplanar waveguide , or a microstrip resonator, , or a transmission line . Planar microcoil, dual antenna, copper strip coil,and surface loop-gap microresonator were also exploited to inductively detect EPR in the DPPH molecule.…”

Microwave Magnetoresistance and Microwave Absorption in Sr2FeMoO6

“…Then, the change in the S 11 parameter (only due to the sample as copper is nonmagnetic) was measured as the dc magnetic field varied in a perpendicular direction in a broad frequency range ( f = 0.1–4.2 GHz). Thus, the power absorbed by the sample on exposure to the magnetic field ( H ) is expressed as Δ P [dB] = 20 log 10 | S 11 ( H max )| – 20 log| S 11 ( H )|, where H max is the maximum magnetic field (2.5 kOe), which is taken as the reference point …”

Paramagnetic resonance in La2NiMnO6 probed by impedance and lock-in detection techniques

“…19 We obtained a g-factor of 1.999 for the standard EPR marker DPPH using the same magnetoimpedance setup and hence the results are reliable. 20 The large g-factor in LNMO indicates significant contribution of orbital magnetic moment and hence a strong spin-orbit coupling in Ni 2+ cation. This is also in agreement with an X-ray magnetic circular dichroism results which suggests that ratio of orbital to spin moment for Ni 2+ is an order of magnitude higher than for Mn 4+ cation.…”