Aspects of the present disclosure are directed to magnetoresistive stacks including regions having increased height-to-diameter ratios. Exemplary magnetoresistive stacks (for example, used in a magnetic tunnel junction (MTJ) magnetoresistive device) of the present disclosure include one or more multilayer synthetic antiferromagnetic structures (SAFs) or synthetic ferromagnetic structures (SyFs) in order to promote stability of the SAF or SyF, e.g., for smaller-sized MTJs.