Related papers: A Wideband Spectrometer for NMR Studies
The work to be described falls into three parts: (1) The computer-controlled CW spectrometer was designed to supplement the Manchester pulsed microwave spectrometer in situations where rapid nuclear relaxation makes spin-echo spectroscopy…
In the search for a novel MRI contrast agent which relies on T1 shortening due to quadrupolar interaction between Bi nuclei and protons, a fast scanning wideband system for zero-field nuclear quadrupole resonance (NQR) spectroscopy is…
We report the observation of novel behaviour in the radio frequency (rf) and microwave response of DyNi_2B_2C over a wide range of temperature (T) and magnetic field (H) in the antiferromagnetic (AFM) and superconducting (SC) states. At…
Nd_0.67Sr_0.33MnO_3 nanoparticles with the grain size of about 30 nm are prepared by sol-gel method.These nanopowders are annealed at four different temperatures viz. 800 oC, 900 oC, 1000 oC and 1100 oC to study the effect of particle size…
We describe a low-cost and simple setup for hyperthermia measurements on colloidal solutions of magnetic nanoparticles (ferrofluids) with a frequency-adjustable magnetic field in the range 5-500 kHz produced by an electromagnet. By…
Non-resonant microwave absorption(NRMA) studies of superconducting MgB_2 at a frequency of 9.43 GHz in the field range -50 Gauss to 5000 Gauss are reported. The NRMA results indicate near absence of intergranular weak links. A linear…
The NMR spectra of paramagnetic substances can feature shifts over thousands of ppm. In high magnetic field instruments, this corresponds to extreme offsets, which make it challenging or impossible to achieve uniform excitation without…
Nuclear magnetic resonance (NMR) spectroscopy provides unparalleled access to molecular structure and dynamics but is traditionally limited by weak signal strength, requiring large sample volumes and high magnetic fields. Here, we…
The ${}^{11}$B NMR spectra in polycrystalline MgB$_2$ were measured for several magnetic fields (1.97 T and 3.15 T) as a function of temperature from 5 K to 40 K. The composite spectra in the superconducting state can be understood in terms…
Low frequency observations at 330 and 74 MHz can provide new insights into supernova remnants (SNR). We can test theoretical predictions for spectral index variations. Nonlinear models of shock acceleration predict that the spectra from…
We describe the development of a broadband magneto-optical spectrometer with femtosecond temporal resolution. The absorption spectrometer is based on a white-light supercontinuum (ca. 320 - 750 nm) using shot-to-shot temporal and spectral…
Measurements of the $^{1}$H-NMR spectrum of a small ($\sim$ 4 $\mu$g) single crystal of the organic conductor $\lambda$-(BETS)$_{2}$FeCl$_{4}$ are reported with an applied magnetic field $\bf{B}$$_{0}$ = 9 T parallel to the a-axis in the…
Nuclear magnetic resonance (NMR) technique benefits from high magnetic field not only due to the field-enhanced measurement sensitivity and resolution, but also because it is a powerful tool to investigate field-induced physics in modern…
An AC susceptometer operating in the range of 10 Hz to 100 kHz and at room temperature is designed, built, calibrated and used to characterize the magnetic behaviour of coated magnetic nanoparticles. Other weakly magnetic materials (in…
A large solid angle magnetic spectrometer for high luminosity and forward scattering angles was constructed at the Thomas Jefferson National Accelerator Facility. A number of physics experiments have used this spectrometer, and a…
We have designed and characterized a cryogenic amplifier for use in $^3$He NMR spectrometry. The amplifier, with a power consumption of $\sim 2.5$ mW, works at temperatures down to 4~K. It has a hi-impedance input for measuring a signal…
We study spectroscopy of negatively charged nitrogen-vacancy center in diamond at high temperatures under high vacuum conditions. Spin resonances are studied using optical detection of magnetic resonance (ODMR), and optical spectroscopy is…
Magnetic nanoparticles of gamma-Fe2O3 coated by organic molecules and suspended in liquid and solid matrices, as well as a non-diluted magnetic fluid have been studied by electron magnetic resonance (EMR) at 77-380 K. Slightly asymmetric…
We report a large enhancement of 1.7 in deuteron polarization up to values of 0.6 due to frequency modulation of the polarizing microwaves in a two liters polarized target using the method of dynamic nuclear polarization. This target was…
A wide-field magnetometer utilizing nitrogen-vacancy (NV) centers in diamond that does not require microwaves is demonstrated. It is designed for applications where microwaves need to be avoided, such as magnetic imaging of biological or…