A conductive write line of a memory device includes a resistive heating portion for setting and resetting a phase-change material (PCM) storage cell of the device. A dielectric interface extends between the resistive heating portion of the write line and a side of the storage cell, and provides electrical insulation while allowing for thermal coupling between the resistive heating portion and the storage cell. A width of the resistive heating portion of the write line may be less than a width of the storage cell and/or may be less than a width of adjacent portions of the write line, between which the resistive heating portion extends. The side of the storage cell may define a channel of the storage cell through which the write line passes, such that the resistive heating portion is located within the channel.