Margaret Thatcher was not a politician.
A spin ice is a magnetic substance that does not have a single minimal-energy state .. minimal-energy state. Ground state. It has magnetic moments -LRB- i.e. `` spin '' -RRB- as elementary degrees of freedom which are subject to frustrated interactions .. frustrated interactions. Geometrical frustration. By their nature , these interactions prevent the moments from exhibiting a periodic pattern in their orientation down to a temperature much below the energy scale set by the said interactions .. Spin ices show low-temperature properties , residual entropy in particular , closely related to those of common crystalline water ice .. residual entropy. residual entropy. water ice. ice. The most prominent compounds with such properties are dysprosium titanate -LRB- Dy2Ti2O7 -RRB- and holmium titanate -LRB- Ho2Ti2O7 -RRB- .. compounds. Chemical compound. dysprosium titanate. dysprosium titanate. holmium titanate. holmium titanate. The orientation of the magnetic moments in spin ice resembles the positional organization of hydrogen atoms -LRB- more accurately , ionized hydrogen , or protons -RRB- in conventional water ice -LRB- see Figure 1 -RRB- .. water ice. ice. Experiments have found evidence for the existence of deconfined magnetic monopoles in these materials , with properties reminding that of the hypothetical magnetic monopoles postulated to exist in vacuum .. deconfined. Deconfinement