Ko te irahiko paramagnetic oro (EPR) he momo hangarau irahiko aukume i ahu mai i te aukume aukume o ngā irahiko kore-hoa. Ka taea te whakamahi hei kimi i ngā irahiko kore-hoa kei roto i ngā ngota, i ngā ngota rānei o ngā matū, me te tūhura i aua mea. Ngā āhuatanga hanganga o te taiao e karapoti ana. Mō ngā rauropi kore utu, kāore he pānga o te aukume porowhita, ā, ko te nuinga o te aukume aukume katoa (neke atu i te 99%) ka whai wāhi ki te takahuri irahiko, nō reira ka kiia hoki te irahiko paramagnetic orohiko ko te "irahiko takahuri irahiko" (ESR).

I kitea tuatahitia te irahiko paramagnetic e te tohunga ahupūngao o mua o Soviet, a E·K·Zavois, i te tau 1944 mai i te MnCl2, CuCl2 me ētahi atu tote paramagnetic. I whakamahia tuatahitia tēnei tikanga e ngā tohunga ahupūngao hei ako i te hanganga hiko, te hanganga tioata, te nekehanga dipole, me te hanganga ngota o ētahi ngota matatini. I runga i ngā hua o ngā inenga irahiko paramagnetic, i whakamāramahia e ngā tohunga matū ngā here matū me ngā tohatoha kiato irahiko i roto i ngā pūhui waro matatini, me ngā raruraru maha e pā ana ki te tikanga tauhohenga. Nā American B. Commoner me ētahi atu i whakauru te hangarau irahiko paramagnetic ki te mara o te koiora mō te wā tuatahi i te tau 1954. I kitea e rātou te noho o ngā rauropi kore utu i roto i ētahi rauemi tipu me te kararehe. Mai i te tekau tau atu i 1960, nā te whakapainga tonu o ngā taputapu me te auahatanga tonu o te hangarau, kua whakamahia te hangarau irahiko paramagnetic i roto i te ahupūngao, ngā semiconductors, te matū waro, te matū matatini, te matū irahiko, te miihini matū, te matū moana, ngā whakakorikori, te koiora, me te koiora. Kua whakamahia whānuitia i roto i ngā mara maha pēnei i te matū, te rongoā, te pūtaiao taiao, me te rapu whenua.