Introduction

Transition metal oxides have recently been the subject of enormous activity within both the applied and basic science communities. However, the overwhelming balance of interest was devoted to 3delements and their binary compounds for many decades, extending from the 19^th to the late 20^th Century. The strong magnetic and elastic properties of these materials were key to various technologies, although the relatively robust superconducting properties of several Nb intermetallic compounds (e.g., Nb₃Sn, NbTi) shifted some attention toward the 4d-elements during the 1960’s.