Using radioactive beams to unravel local phenomena in ferroic and multiferroic materials

The increasing interest in using ferroic and multiferroic materials in high-tech applications requires that the underlying physical phenomena are studied at the atomic scale. Time-differential perturbed angular correlation (TDPAC) measurements have a local character and can provide important information concerning combined magnetic dipole and electric quadrupole interactions in multiferroic systems. With the application of characterization techniques and radioactive beams, this method has become very powerful, especially for the determination of the temperature dependence of hyperfine parameters, even at high temperatures. Such measurements lead to a better understanding of phase transitions, including observations of local environments in low fractions of different phases. Several facilities are in use at ISOLDE-CERN that benefit from the multitude of available ion beams that exist for the use and development of the TDPAC technique. An overview of the prior literature, combined with a discussion of measurement conditions and isotopes, is presented. Particular emphasis is given to the important case of measurements carried out at ISOLDE-CERN employing $^{111m}$ Cd as a probe.